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VCS-256 exam Dumps Source : Administration of Veritas InfoScale Availability 7.1 for UNIX/Linux

Test Code : VCS-256
Test cognomen : Administration of Veritas InfoScale Availability 7.1 for UNIX/Linux
Vendor cognomen : Veritas
: 84 true Questions

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Veritas Administration of Veritas InfoScale

Veritas technologies to deliver govt organizations with data coverage and Cloud features | killexams.com true Questions and Pass4sure dumps

Sep 18, 2018

Stephanie Simone

Veritas technologies, issuer of industry information coverage and utility-described storage options, is getting into a executive-large agreement for the U.S. usual functions Administration (GSA), presenting federal businesses with records governance and cloud facts management software.

below the contract, government groups can own access to Veritas data insurance plot and cloud solutions at negotiated fees to allow for better statistics management.

The settlement is derived from the GSA IT agenda 70 and thoroughly helps the Federal tips expertise Acquisition Reform Act (FITARA) Enhancement application.

The agreement brings Veritas’ commercial enterprise information administration portfolio to bar nonexistent eligible federal, state, native, and tribal govt corporations.

These groups can build upon the data coverage basis of Veritas NetBackup and add further statistics management capabilities to precipitate up their cloud initiatives.

one of the crucial initial choices include:

  • Veritas information perception helps groups enhance unstructured information governance to in the reduction of charges, risk and obtain compliance via actionable intelligence into records ownership, usage and entry controls.
  • Veritas eDiscovery Platform offers governments with the most effectual analysis toolkit for isolating considerable felony, regulatory and investigative items, revealing context and prioritizing what is most important, using a unique utility.
  • Veritas InfoScale helps federal IT groups superior give protection to suggestions and purposes across actual and digital infrastructures. InfoScale minimizes downtime with the aid of presenting inordinate availability and calamity recovery over any distance for vital company functions, together with particular person databases, custom functions and sophisticated multitier functions throughout actual, digital and cloud environments.
  • Veritas industry Vault, when offered as a solution with a FedRAMP authorized utility-as-a service (SaaS) cloud service from bluesource (known as EV247), frees organizations from the overhead of owning, running or managing email and file archives. The EV247 solution is powered by using the area’s main archiving expertise from Veritas. it is a cloud platform, utility archiving solution and managed service multi function.
  • Veritas 360 facts management offers organizations the capacity to radically change their records to address the challenges of end-to-end records management by course of statistics visibility, compliance readiness, industry continuity, information coverage and recoverability. It accomplishes bar nonexistent of these dreams while retaining facts/workload portability and storage optimization.
  • For extra counsel about this information, seek counsel from www.veritas.com.


    Veritas Enters current government-vast Cloud records management agreement for the U.S. accepted services Administration | killexams.com true Questions and Pass4sure dumps

    MOUNTAIN VIEW, Calif., Sept. 12, 2018 /PRNewswire/ -- Veritas applied sciences, the global market share leader in the enterprise data protection and software-described storage market, has entered into a govt-broad settlement for the U.S. benchmark services Administration (GSA) to give federal agencies with information governance and cloud information administration utility.

    below the agreement, executive groups can own access to Veritas information insurance plot and cloud solutions at negotiated expenditures to permit for improved records management. The constrict is derived from the GSA IT agenda 70 and totally supports the Federal counsel know-how Acquisition Reform Act (FITARA) Enhancement program.

    The agreement brings Veritas' award-profitable commercial enterprise records administration portfolio to bar nonexistent eligible federal, state, indigenous and tribal government companies. These agencies can construct upon the information insurance policy basis of Veritas NetBackup and add additional statistics management capabilities to precipitate up their cloud initiatives. one of the most prefatory choices consist of:

  • Veritas information insight helps corporations enhance unstructured records governance to slash back costs, possibility and achieve compliance via actionable intelligence into facts ownership, usage and entry controls.
  • Veritas eDiscovery Platform offers governments with the ideal evaluation toolkit for keeping apart primary prison, regulatory and investigative objects, revealing context and prioritizing what's most essential, the usage of a unique utility.
  • Veritas InfoScale helps federal IT teams improved give protection to tips and functions across physical and virtual infrastructures. InfoScale minimizes downtime by using offering towering availability and calamity recovery over any distance for crucial company services, together with individual databases, custom applications and complicated multitier functions across physical, virtual and cloud environments.
  • Veritas commercial enterprise Vault, when provided as a solution with a FedRAMP authorized application-as-a carrier (SaaS) cloud provider from bluesource (referred to as EV247), frees businesses from the overhead of possessing, running or managing e mail and file archives. The EV247 reply is powered by course of the area's main archiving know-how from Veritas. it's a cloud platform, application archiving reply and managed provider bar nonexistent in one.
  • Veritas 360 data management offers organizations the capability to radically change their facts to tackle the challenges of conclusion-to-conclusion data management by means of information visibility, compliance readiness, company continuity, data protection and recoverability. It accomplishes bar nonexistent of those purpose while maintaining statistics/workload portability and storage optimization.
  • "The IT time table 70 FITARA Enhancement software will provide govt businesses with superior flexibility in having access to the imaginative utility solutions they want at a stronger price to taxpayers," talked about Alan Thomas, GSA Federal Acquisition service (FAS) Commissioner. "featuring these solutions via a govt-huge, enterprise-degree constrict is a pretty pleasurable option to reduce duplication in their procurement procedure."

    "With the upward shove of cybercrime, the introduction of current records regulations, an upturn of facts growth and escalation of digital privacy, federal agencies nowadays own to be organized to beget strategic selections round records assortment, records storage, the vicinity of that statistics—and how it will likewise be safeguarded," talked about Tom Kennedy, vice president and commonplace supervisor, Veritas Public Sector. "as the undisputed leader in data protection and application-described storage, Veritas is providing government groups convenient access to solutions that back combat these pressures – to recollect records, preserve it covered, enrich statistics availability, unencumber the punch of information and garner insights to compel advancements in govt programs." 

    in regards to the IT agenda 70 FITARA Enhancement ProgramThe Federal suggestions technology Acquisition Reform Act (FITARA) is a GSA software designed to beget it less difficult and extra reasonably priced for federal businesses to acquire application. FITARA was handed by means of Congress in 2014 and the office of management and finances (OMB) implemented assistance in 2016. It aims to reduce prices and convey innovative expertise to the federal government.

    About VeritasVeritas applied sciences is the chief in the global industry information insurance plot and application-described storage market. We aid probably the most considerable businesses on the earth, together with 86 p.c of the international Fortune 500, returned up and recuperate their statistics, sustain it cozy and accessible, asylum in opposition t failure and obtain regulatory compliance. As companies modernize their IT infrastructure, Veritas promises the know-how that helps them slash back dangers and capitalize on their facts. be trained more at www.veritas.com or follow us on Twitter at @veritastechllc.

    Veritas and the Veritas emblem are logos or registered logos of Veritas technologies LLC or its associates in the U.S. and different countries. different names can be logos of their respective house owners.

    PR Contact

    Veritas TechnologiesDayna Fried +1 925 493 9020dayna.fried@veritas.com

     

    Cision View fashioned content material to download multimedia:https://www.prnewswire.com/information-releases/veritas-enters-new-govt-wide-cloud-statistics-administration-settlement-for-the-us-typical-capabilities-administration-300710751.html

    supply Veritas applied sciences


    Veritas Boosts application performance and Streamlines data protection and administration on AWS | killexams.com true Questions and Pass4sure dumps

    LAS VEGAS--(business WIRE)--Veritas applied sciences, the leader in guidance administration, nowadays announced at AWS re:Invent current capabilities for InfoScale and NetBackup designed to optimize enterprise utility migration and simplify statistics protection deployment inside Amazon net features (AWS) environments. Veritas InfoScale offers software-defined storage for the cloud and helps ensure software performance, scale and resiliency requirements are met. moreover, maintaining these functions and other cloud-based mostly workloads has now been made even less complicated with the brand current Amazon computing device photo (AMI) for NetBackup. These newest capabilities be section of a bunch of latest Veritas cloud statistics management options that back plenty of AWS exhaust circumstances, from data governance and insurance policy to migration and catastrophe restoration.

    As businesses appear to shift from upfront capex investments to pay-as-you-go opex models, many are prioritizing AWS substances to replace expensive on-premises infrastructure. in reality, in response to Veritas analysis, fifty three p.c of mission-essential functions could be within the public cloud this year. This accelerating shift indicates that earlier than refreshing on-premises hardware, groups are looking first to the cloud. although, one primary roadblock to with ease “lifting and moving” functions devotion Oracle, SAP, and other resource intensive workloads is the performance and resiliency tradeoffs. whereas IT has the alternative of refactoring these purposes to drudgery natively within the cloud, doing so can be each a large time dedication and a pricey conducting.

    Veritas InfoScale allows the precipitate and price-effectiveness of lifting and transferring to AWS whereas assisting be positive the performance, scalability and resiliency of these enterprise applications. the brand current NetBackup AMI simplifies records insurance policy deployment—both in and out of the cloud—as section of the NetBackup platform’s unique pane of glass adventure and finished solution to protect bar nonexistent actual, digital and cloud-based workloads.

    these days’s announcement serves as an considerable proof aspect of Veritas’ course to bring cloud data administration options that tackle bar nonexistent predominant areas of cloud transformation:

  • world statistics Visibility – Blindly touching statistics and purposes to the cloud can pressure up saturate and enlarge possibility. definitely, fifty two % of enterprise storage budgets are already spent on storing darkish facts. With counsel Map, agencies be alert what facts they own got, who owns it and the course ancient it's, featuring the insight vital to ensure they are relocating the commandeer facts, to the birthright region, at the commandeer time.
  • basic Cloud Migration – devoid of the commandeer equipment, migrating data and application workloads to the cloud can prove to be a complicated and costly activity. To provide essential and in your price orbit cloud migration, Veritas leverages the profound information of statistics and software interdependencies constructed into InfoScale to alleviate storage bottlenecks and enable seamless and bright statistics migration to the AWS cloud. groups with hybrid-cloud ideas can now profit the identical elevated workload portability, resiliency and manage in the cloud that they are used to on-premises.
  • Optimized utility efficiency – Lifting and transferring commercial enterprise applications to the cloud can impose inordinate efficiency tradeoffs. The software-consciousness and bright statistics caching constructed into InfoScale utility-defined storage choices alleviates these trade-offs, giving valued clientele an accelerated, yet commercial enterprise-capable atmosphere to maximize mission-essential software performance in the cloud. This skill that groups with mission considerable tier-one applications comparable to Oracle, TIBCO, SAP and other OLTP/OLAP workloads, can now select skills of the size and economics of AWS infrastructure with out sacrificing required performance and reliability.
  • Unified records insurance policy – The complexity of keeping information the usage of aspect products is exponentially larger with the adoption of discrete cloud infrastructures. NetBackup grants an easy, official and unified facts protection journey that siloed and disparate products can not deliver. With the unlock of NetBackup eight.0, AWS shoppers can now leverage the current NetBackup AMI for a preconfigured and customizable cloud deployment of NetBackup in minutes.
  • “Our purchasers are leveraging Veritas solutions to integrate Amazon S3 into their facts lifecycle management approach,” observed Mike Palmer, executive vice president, chief product officer at Veritas. “hobby in relocating tier-one enterprise functions similar to Oracle and SAP to the cloud is transforming into. Veritas is leading the efforts to enable these organizations own a seamless, scalable and cost-efficient solution to entry, share and leverage cloud storage without having to sacrifice efficiency or resiliency.”

    “As extra agencies increasingly flip to a considerable number of styles of clouds to eschew some or bar nonexistent of their mission-critical functions, the capability to migrate and control statistics between and across systems—now not just at all, but effortlessly—becomes vital,” referred to tag Peters, follow Director & Senior Analyst, enterprise course group. “with the aid of growing options for these hybrid cloud environments, and chiefly building-in sheperd for AWS, Veritas is providing customers with an effectual strategy to both control their facts and likewise to gain seamless entry to the area’s greatest public cloud issuer.”

    Veritas is a gold sponsor of AWS re:Invent 2016. For convention attendees attracted to researching more about Veritas cloud information administration choices for AWS, gladden contend with us at sales space #632. also, celebrate us on twitter @Veritasllc and interact with us the exhaust of #reInvent or #ReInvent2016.

    About Veritas technologies

    Veritas applied sciences allows for organizations to harness the energy of their counsel, with suggestions management solutions serving the realm’s biggest and most advanced environments. Veritas works with agencies of bar nonexistent sizes, including 86 percent of world Fortune 500 corporations, enhancing records availability and revealing insights to compel aggressive knowledge. www.veritas.com


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    King of the network operating systems | killexams.com true questions and Pass4sure dumps

    COMPUTINGFrom...Network World Fusion networking

    January 24, 2000Web posted at: 12:11 p.m. EST (1711 GMT)

    by John Bass and James Robinson, Network World Test Alliance

    (IDG) -- It bar nonexistent boils down to what you're looking for in a network operating system (NOS).

    Do you want it skinny and springy so you can install it any course you please? Perhaps administration bells and management whistles are what you requisite so you can deploy several hundred servers. Or maybe you want an operating system that's robust enough so that you sleep devotion a baby at night?

    The pleasurable word is that there is a NOS waiting just for you. After the rash of recent software revisions, they took an in-depth contemplate at four of the major NOSes on the market: Microsoft's Windows 2000 Advanced Server, Novell's NetWare 5.1, Red Hat Software's Linux 6.1 and The Santa Cruz Operation's (SCO) UnixWare 7.1.1. Sun declined their invitation to submit Solaris because the company says it's working on a current version.

    Microsoft's Windows 2000 edges out NetWare for the Network World Blue Ribbon Award. Windows 2000 tops the field with its management interface, server monitoring tools, storage management facilities and security measures.

    However, if it's performance you're after, no product came nigh to Novell's NetWare 5.1's numbers in their exhaustive file service and network benchmarks. With its lightning-fast engine and Novell's directory-based administration, NetWare offers a much foundation for an enterprise network.

    We found the latest release of Red Hat's commercial Linux bundle led the list for flexibility because its modular design lets you pare down the operating system to suit the job at hand. Additionally, you can create scripts out of multiple Linux commands to automate tasks across a distributed environment.

    While SCO's UnixWare seemed to lag behind the pack in terms of file service performance and NOS-based administration features, its scalability features beget it a stout candidate for running enterprise applications.

    The numbers are in

    Regardless of the job you saddle your server with, it has to execute well at reading and writing files and sending them across the network. They designed two benchmark suites to measure each NOS in these two categories. To reflect the true world, their benchmark tests account a wide orbit of server conditions.

    NetWare was the hands-down leader in their performance benchmarking, taking first space in two-thirds of the file tests and earning top billing in the network tests.

    Red Hat Linux followed NetWare in file performance overall and even outpaced the leader in file tests where the read/write loads were small. However, Linux did not execute well handling large loads - those tests in which there were more than 100 users. Under heavier user loads, Linux had a tendency to discontinue servicing file requests for a short period and then start up again.

    Windows 2000 demonstrated penniless write performance across bar nonexistent their file tests. In fact, they found that its write performance was about 10% of its read performance. After consulting with both Microsoft and Client/Server Solutions, the author of the Benchmark Factory testing appliance they used, they determined that the penniless write performance could be due to two factors. One, which they were unable to verify, might be a workable performance problem with the SCSI driver for the hardware they used.

    More significant, though, was an issue with their test software. Benchmark Factory sends a write-through flag in each of its write requests that is supposititious to judgement the server to update cache, if appropriate, and then compel a write to disk. When the write to disk occurs, the write convene is released and the next request can be sent.

    At first glance, it appeared as if Windows 2000 was the only operating system to veneration this write-through flag because its write performance was so poor. Therefore, they ran a second round of write tests with the flag turned off.

    With the flag turned off, NetWare's write performance increased by 30%. This test proved that Novell does indeed veneration the write-through flag and will write to disk for each write request when that flag is set. But when the write-through flag is disabled, NetWare writes to disk in a more efficient manner by batching together contiguous blocks of data on the cache and writing bar nonexistent those blocks to disk at once.

    Likewise, Red Hat Linux's performance increased by 10% to 15% when the write-through flag was turned off. When they examined the Samba file system code, they found that it too honors the write-through flag. The Samba code then finds an optimum time during the read/write sequence to write to disk.

    This second round of file testing proves that Windows 2000 is conditional on its file system cache to optimize write performance. The results of the testing with the write-through flag off were much higher - as much as 20 times faster. However, Windows 2000 soundless fell behind both NetWare and RedHat Linux in the file write tests when the write-through flag was off.

    SCO honors the write-through flag by default, since its journaling file system is constructed to maximize data integrity by writing to disk for bar nonexistent write requests. The results in the write tests with the write-through flag on were very similar to the test results with the write-through flag turned off.

    For the network benchmark, they developed two tests. Their long TCP transaction test measured the bandwidth each server can sustain, while their short TCP transaction test measured each server's aptitude to wield large numbers of network sessions with minuscule file transactions.

    Despite a penniless showing in the file benchmark, Windows 2000 came out on top in the long TCP transaction test. Windows 2000 is the only NOS with a multithreaded IP stack, which allows it to wield network requests with multiple processors. Novell and Red Hat relate they are working on integrating this capability into their products.

    NetWare and Linux likewise registered stout long TCP test results, coming in second and third, respectively.

    In the short TCP transaction test, NetWare came out the pellucid winner. Linux earned second space in spite of its want of back for abortive TCP closes, a course by which an operating system can quickly tear down TCP connections. Their testing software, Ganymede Software's Chariot, uses abortive closes in its TCP tests.

    Moving into management

    As enterprise networks grow to require more servers and back more cessation users, NOS management tools become crucial elements in keeping networks under control. They looked at the management interfaces of each product and drilled down into how each handled server monitoring, client administration, file and print management, and storage management.

    We found Windows 2000 and NetWare provide equally useful management interfaces.

    Microsoft Management Console (MMC) is the glue that holds most of the Windows 2000 management functionality together. This configurable graphical user interface (GUI) lets you snap in Microsoft and third-party applets that customize its functionality. It's a two-paned interface, much devotion Windows Explorer, with a nested list on the left and selection details on the right. The console is effortless to exhaust and lets you configure many local server elements, including users, disks, and system settings such as time and date.

    MMC likewise lets you implement management policies for groups of users and computers using active Directory, Microsoft's current directory service. From the active Directory management appliance inside MMC, you can configure users and change policies.

    The network configuration tools are found in a part application that opens when you click on the Network Places icon on the desktop. Each network interface is listed inside this window. You can add and change protocols and configure, enable and disable interfaces from here without rebooting.

    NetWare offers several interfaces for server configuration and management. These tools proffer duplicate functionality, but each is useful depending from where you are trying to manage the system. The System Console offers a number of tools for server configuration. One of the most useful is NWConfig, which lets you change start-up files, install system modules and configure the storage subsystem. NWConfig is simple, intuitive and predictable.

    ConsoleOne is a Java-based interface with a few graphical tools for managing and configuring NetWare. Third-party administration tools can plug into ConsoleOne and let you manage multiple services. They contemplate ConsoleOne's interface is a bit unsophisticated, but it works well enough for those who must own a Windows- based manager.

    Novell likewise offers a Web-accessible management application called NetWare Management Portal, which lets you manage NetWare servers remotely from a browser, and NWAdmin32, a relatively simple client-side appliance for administering Novell Directory Services (NDS) from a Windows 95, 98 or NT client.

    Red Hat's overall systems management interface is called LinuxConf and can eschew as a graphical or text-based application. The graphical interface, which resembles that of MMC, works well but has some layout issues that beget it difficult to exhaust at times. For example, when you eschew a setup application that takes up a lot of the screen, the system resizes the application larger than the desktop size.

    Still, you can manage pretty much anything on the server from LinuxConf, and you can exhaust it locally or remotely over the Web or via telnet. You can configure system parameters such as network addresses; file system settings and user accounts; and set up add-on services such as Samba - which is a service that lets Windows clients score to files residing on a Linux server - and FTP and Web servers. You can apply changes without rebooting the system.

    Overall, Red Hat's interface is useful and the underlying tools are powerful and flexible, but LinuxConf lacks the polish of the other vendors' tools.

    SCO Admin is a GUI-based front cessation for about 50 SCO UnixWare configuration and management tools in one window. When you click on a tool, it brings up the application to manage that detail in a part window.

    Some of SCO's tools are GUI-based while others are text-based. The server required a reboot to apply many of the changes. On the plus side, you can manage multiple UnixWare servers from SCOAdmin.

    SCO likewise offers a useful Java-based remote administration appliance called WebTop that works from your browser.

    An eye on the servers and clients

    One considerable administration job is monitoring the server itself. Microsoft leads the pack in how well you can sustain an eye on your server's internals.

    The Windows 2000 System Monitor lets you view a real-time, running graph of system operations, such as CPU and network utilization, and remembrance and disk usage. They used these tools extensively to determine the consequence of their benchmark tests on the operating system. Another appliance called Network Monitor has a basic network packet analyzer that lets you contemplate the types of packets coming into the server. Together, these Microsoft utilities can be used to compare performance and capacity across multiple Windows 2000 servers.

    NetWare's Monitor utility displays processor utilization, remembrance usage and buffer utilization on a local server. If you know what to contemplate for, it can be a powerful appliance for diagnosing bottlenecks in the system. Learning the import of each of the monitored parameters is a bit of a challenge, though.

    If you want to contemplate at performance statistics across multiple servers, you can tap into Novell's Web Management Portal.

    Red Hat offers the benchmark Linux command-line tools for monitoring the server, such as iostat and vmstat. It has no graphical monitoring tools.

    As with any Unix operating system, you can write scripts to automate these tools across Linux servers. However, these tools are typically cryptic and require a towering flush of proficiency to exhaust effectively. A suite of graphical monitoring tools would be a much addition to Red Hat's Linux distribution.

    UnixWare likewise offers a number of monitoring tools. System Monitor is UnixWare's simple but limited GUI for monitoring processor and remembrance utilization. The sar and rtpm command-line tools together list real-time system utilization of buffer, CPUs and disks. Together, these tools give you a pleasurable overall faith of the load on the server.

    Client administration

    Along with managing the server, you must manage its users. It's no astound that the two NOSes that ship with an integrated directory service topped the field in client administration tools.

    We were able to configure user permissions via Microsoft's active Directory and the directory administration appliance in MMC. You can group users and computers into organizational units and apply policies to them.

    You can manage Novell's NDS and NetWare clients with ConsoleOne, NWAdmin or NetWare Management Portal. Each can create users, manage file space, and set permissions and rights. Additionally, NetWare ships with a five-user version of Novell's ZENworks tool, which offers desktop administration services such as hardware and software inventory, software distribution and remote control services.

    Red Hat Linux doesn't proffer much in the course of client administration features. You must control local users through Unix authorization configuration mechanisms.

    UnixWare is similar to Red Hat Linux in terms of client administration, but SCO provides some Windows binaries on the server to remotely set file and directory permissions from a Windows client, as well as create and change users and their settings. SCO and Red Hat proffer back for the Unix-based Network Information Service (NIS). NIS is a store for network information devotion logon names, passwords and home directories. This integration helps with client administration.

    Handling the staples: File and print

    A NOS is nothing without the aptitude to share file storage and printers. Novell and Microsoft collected top honors in these areas.

    You can easily add and maintain printers in Windows 2000 using the print administration wizard, and you can add file shares using active Directory management tools. Windows 2000 likewise offers Distributed File Services, which let you combine files on more than one server into a unique share.

    Novell Distributed Print Services (NDPS) let you quickly incorporate printers into the network. When NDPS senses a current printer on the network, it defines a Printer Agent that runs on the printer and communicates with NDS. You then exhaust NDS to define the policies for the current printer.

    You define NetWare file services by creating and then mounting a disk volume, which likewise manages volume policies.

    Red Hat includes Linux's printtool utility for setting up server-connected and networks printers. You can likewise exhaust this GUI to create printcap entries to define printer access.

    Linux has a set of command-line file system configuration tools for mounting and unmounting partitions. Samba ships with the product and provides some integration for Windows clients. You can configure Samba only through a cryptic configuration ASCII file - a grave drawback.

    UnixWare provides a springy GUI-based printer setup appliance called Printer SetUp Manager. For file and volume management, SCO offers a appliance called VisionFS for interoperability with Windows clients. They used VisionFS to allow their NT clients to access the UnixWare server. This service was effortless to configure and use.

    Storage management

    Windows 2000 provides the best tools for storage management. Its graphical Manage Disks appliance for local disk configuration includes software RAID management; you can dynamically add disks to a volume set without having to reboot the system. Additionally, a signature is written to each of the disks in an array so that they can be moved to another 2000 server without having to configure the volume on the current server. The current server recognizes the drives as members of a RAID set and adds the volume to the file system dynamically.

    NetWare's volume management tool, NWConfig, is effortless to use, but it can be a petite confusing to set up a RAID volume. Once they knew what they were doing, they had no problems formatting drives and creating a RAID volume. The appliance looks a petite primitive, but they give it towering marks for functionality and ease of use.

    Red Hat Linux offers no graphical RAID configuration tools, but its command line tools made RAID configuration easy.

    To configure disks on the UnixWare server, they used the Veritas Volume Manager graphical disk and volume administration appliance that ships with UnixWare. They had some problems initially getting the appliance to recognize the drives so they could be formatted. They managed to drudgery around the disk configuration problem using an assortment of command line tools, after which Volume Manager worked well.

    Security

    While they did not probe these NOSes extensively to expose any security weaknesses, they did contemplate at what they offered in security features.

    Microsoft has made significant strides with Windows 2000 security. Windows 2000 supports Kerberos public key certificates as its primary authentication mechanism within a domain, and allows additional authentication with smart cards. Microsoft provides a Security Configuration appliance that integrates with MMC for effortless management of security objects in the active Directory Services system, and a current Encrypting File System that lets you designate volumes on which files are automatically stored using encryption.

    Novell added back for a public-key infrastructure into NetWare 5 using a public certificate schema developed by RSA Security that lets you tap into NDS to generate certificates.

    Red Hat offers a basic Kerberos authentication mechanism. With Red Hat Linux, as with most Unix operating systems, the network services can be individually controlled to enlarge security. Red Hat offers Pluggable Authentication Modules as a course of allowing you to set authentication policies across programs running on the server. Passwords are protected with a shadow file. Red Hat likewise bundles firewall and VPN services.

    UnixWare has a set of security tools called Security Manager that lets you set up varying degrees of intrusion protection across your network services, from no restriction to turning bar nonexistent network services off. It's a pleasurable management time saver, though you could manually modify the services to achieve the identical result.

    Stability and failing tolerance

    The most feature-rich NOS is of petite value if it can't sustain a server up and running. Windows 2000 offers software RAID 0, 1 and 5 configurations to provide failing tolerance for onboard disk drives, and has a built-in network load-balancing feature that allows a group of servers to contemplate devotion one server and share the identical network cognomen and IP address. The group decides which server will service each request. This not only distributes the network load across several servers, it likewise provides failing tolerance in case a server goes down. On a lesser scale, you can exhaust Microsoft's Failover Clustering to provide basic failover services between two servers.

    As with NT 4.0, Windows 2000 provides remembrance protection, which means that each process runs in its own segment.

    There are likewise backup and restore capabilities bundled with Windows 2000.

    Novell has an add-on product for NetWare called Novell Cluster Services that allows you to cluster as many as eight servers, bar nonexistent managed from one location using ConsoleOne, NetWare Management Portal or NWAdmin32. But Novell presently offers no clustering products to provide load balancing for applications or file services. NetWare has an intricate remembrance protection scheme to segregate the remembrance used for the kernel and applications, and a Storage Management Services module to provide a highly springy backup and restore facility. Backups can be all-inclusive, cover parts of a volume or store a differential snapshot.

    Red Hat provides a load-balancing product called piranha with its Linux. This package provides TCP load balancing between servers in a cluster. There is no arduous circumscribe to the number of servers you can configure in a cluster. Red Hat Linux likewise provides software RAID back through command line tools, has remembrance protection capabilities and provides a rudimentary backup facility.

    SCO provides an optional feature to cluster several servers in a load-balancing environment with Non-Stop Clustering for a towering flush of fault-tolerance. Currently, Non-Stop Clustering supports six servers in a cluster. UnixWare provides software RAID back that is managed using SCO's On-Line Data Manager feature. bar nonexistent the benchmark RAID levels are supported. Computer Associates' bundled ArcServeIT 6.6 provides backup and restore capabilities. UnixWare has remembrance protection capabilities.

    Documentation

    Because their testing was conducted before Windows 2000's common availability ship date, they were not able to evaluate its hard-copy documentation. The online documentation provided on a CD is extensive, useful and well-organized, although a Web interface would be much easier to exhaust if it gave more than a yoke of sentences at a time for a particular wait on topic.

    NetWare 5 comes with two manuals: a circumstantial manual for installing and configuring the NOS with pleasurable explanations of concepts and features along with an overview of how to configure them, and a minuscule spiral-bound booklet of quick start cards. Novell's online documentation is very helpful.

    Red Hat Linux comes with three manuals - an installation guide, a getting started sheperd and a reference manual - bar nonexistent of which are effortless to follow.

    Despite being the most difficult product to install, UnixWare offers the best documentation. It comes with two manuals: a system handbook and a getting started guide. The system handbook is a reference for conducting the installation of the operating system. It does a pleasurable job of reflecting this painful experience. The getting started sheperd is well-written and well-organized. It covers many of the tools needed to configure and maintain the operating system. SCO's online documentation looks nice and is effortless to follow.

    Wrapping up

    The bottom line is that these NOSes proffer a wide orbit of characteristics and provide enterprise customers with a much deal of option regarding how each can be used in any given corporate network.

    If you want a good, common purpose NOS that can deliver enterprise-class services with bar nonexistent the bells and whistles imaginable, then Windows 2000 is the strongest contender. However, for towering performance, enterprise file and print services, their tests expose that Novell leads the pack. If you're willing to pay a higher price for scalability and reliability, SCO UnixWare would be a safe bet. But if you requisite an inexpensive alternative that will give you bare-bones network services with decent performance, Red Hat Linux can certainly meet the bill.

    The option is yours.

    Bass is the technical director and Robinson is a senior technical staff member at Centennial Networking Labs (CNL) at North Carolina status University in Raleigh. CNL focuses on performance, capacity and features of networking and server technologies and equipment.

    RELATED STORIES:

    Debate will focus on Linux vs. LinuxJanuary 20, 2000Some Windows 2000 PCs will jump the gunJanuary 19, 2000IBM throws Linux lovefestJanuary 19, 2000Corel Linux will eschew Windows appsJanuary 10, 2000Novell's eDirectory spans platformsNovember 16, 1999New NetWare embraces Web appsNovember 2, 1999Microsoft sets a date for Windows 2000October 28, 1999

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    Fusion's Forum: Square off with the vendors over who has the best NOS(Network World Fusion)How they did it: Details of the testing(Network World Fusion)Find out the tuning parameters(Network World Fusion)Download the Config files(Network World Fusion)The Shootout results(Network World Fusion)Fusion's NOS resources(Network World Fusion)With Windows 2000, NT grows up(Network World Fusion)Fireworks expected at NOS showdown(Network World Fusion)

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    New Products | killexams.com true questions and Pass4sure dumps

    New Products

    ActiveBatch Gets Blackberry Functionality

    Administrators own long been able to receive pages when servers travel down, but now they can restart servers with their pagers. Advanced Systems Concepts Inc. has added the Blackberry line of pagers to its list of clients for the ActiveBatch Job Scheduling and Management System.

    The ActiveBatch Wireless Client is a module for the management software that enables administrators to monitor systems and initiate processes from the Blackberry. ActiveBatch Job Scheduling and Management System allows users to set up calendars to initiate processes such as backups or printing, or initiate processes from remote clients.

    Ben Rosenberg, CEO of Advanced Systems, says the company chose to back the Blackberry first since it was the handheld best suited for round-the-clock monitoring. "The battery life is three weeks, and it’s always on," he says. Advanced Systems supports both the pager-sized and PDA-sized Blackberries.

    If a system sends out an SNMP signal, administrators can configure the system to dispatch an e-mail to a Blackberry, alerting the administrator. The e-mail gives the administrator the option to initiate processes, such as rebooting a server, through the Blackberry. "With the Blackberry, e-mails are always actionable by you," Rosenberg says.

    Rosenberg sees two advantages to system management through wireless devices. First, it obviates the requisite to give instructions over the phone to a less experienced operator. Second, high-level administrators who travel can sustain an eye on the system. "If you’re on the road, you’re able to know if something is wrong," he says. With both advantages, administrators will be better able to guarantee uptime, with less impact on their lives.

    In addition to the three levels of encryption standards on Blackberry devices, ActiveBatch provides additional security features, such as a password login to the system. This keeps random users, including thieves, from wreaking havoc on corporate systems. "Use of ActiveBatch is always secure," Rosenberg says.

    ActiveBatch can manage Windows, OpenVMS and Unix-based systems with an agent on each server. The agent sends information to a central Windows console. The software integrates with the Windows Management Instrument, which likewise serves as a SNMP provider. ActiveBatch provides three plug-ins for remote clients: e-mail, browser and now the Blackberry.

    Rosenberg says Advanced Systems is working to bring ActiveBatch to PocketPC handhelds. He says that although users can already exhaust them with the browser-based system, the company will accommodate the system to better meet the needs and limitations of the PocketPC platform.

    Contact: Advanced Systems Concepts Inc., www.advsyscon.com, (201) 798-6400

    SafeStone Provides iSeries back to RSA Security

    Security management provider SafeStone Technologies plc. has added iSeries 400 features to an existing partnership with RSA Security Inc. Under the enhanced agreement, SafeStone is making RSA’s SecurID authentication appliance usable on an iSeries 400 platform.

    Using its DetectIT Agent 400 interface, SafeStone is enabling two-factor authentication. Two-factor authentication requires an individual to be verified twice before access is allowed to systems.

    DetectIT is an offering designed by SafeStone to protect iSeries 400 exit points from unauthorized user access to confidential data, application and resources within an open-connectivity environment.

    Through DetectIT, RSA’s iSeries-based users will be able to leverage software solutions for auditing, data and system management, e-business security, and application and access control for unique or multiple networked iSeries 400s.

    As section of its agreement with RSA, SafeStone will act as RSA’s IBM iSeries industry partner, handling bar nonexistent sales and back responsibility for DetectIT. In this role, SafeStone, which is likewise an IBM ally for systems management and development, will proffer DetectIT to RSA’s customers as either a standalone or fully integrated offering.

    Contact: RSA Security, Inc., www.rsa.com, (781) 301-5000

    SafeStone Technologies plc, www.safestone.com

    Vendors beget Linux Itanium-Ready

    With Intel Corp.’s May release of its 64-bit Itanium processor, Linux vendors are lining up to back the current architecture. Red Hat Inc., TurboLinux Inc., SuSE AG and Caldera International Inc. bar nonexistent formally released distributions for Itanium.

    To coincide with the announcement, TurboLinux released its Operating System 7 for the Itanium processor. "It’s production-ready," says Thrane Jensen, product manager for Itanium. However, Jensen admits that many users will exhaust early Itanium machines for testing and development, rather than using them in production environments yet.

    Bill Claybrook, research director for Linux and open source at the Aberdeen Group, confirms that "most people are waiting for McKinley." He believes that users will wait for Intel to release McKinley—its second-generation IA-64 processor—before they integrate IA-64 into their environments. "They’re being a petite bit leery of it [in] a production environment," he says. Jensen says TurboLinux is working on its McKinley version of Linux already.

    Jensen says that porting Linux to the IA-64 processor had its challenges. The 64-bit nature of the processor created challenging issues for touching applications over to the current chip. "Dependencies on 32-bit create problems," he says. Some applications addressed specific 32-bit features that did not exist in Itanium. For the most part, applications could be recompiled for the chip. "In general, it’s along the identical code line," he says, "but the kernel has [alot of] different stuff."

    In addition to the core operating system, Jensen says many accepted Linux applications are likewise ready for prime time. Apache and other commonly used applications are production-ready, but "ISVs are going to be doing more application development," he says.

    Red Hat released its Red Hat Linux 7.1 for the Itanium processor in mid-June. Using the 2.4 kernel, Red Hat positions the current release as a platform for testing 64-bit applications ported from 32-bit and RISC machines. The distribution is likewise suited to enterprise server needs; it runs on up to eight processors and offers current configuration tools for BIND, Apache and printing.

    At the identical time, Linux vendor SuSE released an Itanium-specific distribution. SuSE Linux 7.2 for IA-64 uses six CD-ROMs to carry over 1,500 applications for the emerging platform. devotion Red Hat, the company bills the package as a solution for evaluating and deploying Itanium-based servers.

    Although a preview version was already available from the Caldera FTP site at ftp.caldera.com/ia64, Caldera released two current versions in May, accompanied by a public announcement. The final production version of OpenLinux Server 64 should be available late in the third quarter.

    Biff Traber, senior vice president and common manager of the server industry line at Caldera, says Caldera has petite to lose by waiting to release a production version. Customers will contemplate to the distribution for evaluation purposes, so a beta release meets their needs. "It’s a combination of testing, development and prototyping," he says.

    The Trillian project, which initiated development of a Linux kernel for the Itanium processor, first released a kernel in February 2000, predating Itanium’s common availability by over a year. Intel was aggressive in getting prototype chips to developers to ensure a market providing hardware, remote servers and emulators to enable open source developers to own Linux ready for the release date.

    The project later changed its cognomen to the more formal-sounding IA-64 Linux Project and worked to further enhance the development of Linux on Itanium. Itanium is not the first 64-bit platform to eschew Linux—there were already flavors of Linux for Sun Microsystems Inc.’s Sparc processor and Compaq Computer Corp.’s Alpha. In addition to the distributors, the IA-64 Linux Project likewise boasted hardware vendors, Hewlett-Packard Co., IBM Corp., Silicon Graphics Inc., VA Linux Systems Inc. and NEC Corp., as well as Intel and Swiss research laboratory CERN.


    More About Filesystems | killexams.com true questions and Pass4sure dumps

    This chapter is from the book 

    If they account filesystems as a mechanism for both storing and locating data, then the two key elements for any filesystem are the items being stored and the list of where those items are. The deeper details of how a given filesystem manipulates its data and meta-information travel beyond the scope of this chapter but are addressed further in Appendix B, "Anatomy of a Filesystem."

    Filesystem Components That the Admin Needs to Know About

    As always, they requisite to score a wield on the vocabulary before they can understand how the elements of a filesystem drudgery together. The next three sections portray the basic components with which you, as a sysadmin, requisite to be familiar.

    Files

    The most intuitively obvious components of a filesystem are, of course, its files. Because everything in UNIX is a file, special functions are differentiated by file type. There are fewer file types than you might imagine, as Table 3.2 shows.

    Table 3.2 File Types and Purposes, with Examples

    File Type

    Purpose/Contents

    Examples

    Directory

    Maintains information for directory structure

    /

    /usr

    /etc

    Block special

    Buffered device file

    Linux: /dev/hda1

    Solaris: /dev/dsk/c0t0d0s0

    Character special

    Raw device file

    Linux: /dev/tty0

    Solaris: /dev/rdsk/c0t0d0s0

    UNIX domain socket

    Interprocess communication (IPC)

    See output of commands for files Linux: netstat –x Solaris: netstat -f unix

    Named pipe special (FIFO device)

    First-in-first-out IPC mechanism, Invoked by name

    Linux: /dev/initctl Solaris: /etc/utmppipe/etc/cron.d/FIFO

    Symbolic link

    Pointer to another file (any type)

    /usr/tmp -> ../var/tmp

    Regular

    All other files; holds data of bar nonexistent other types

    Text files demur files Database files Executables/binaries

    Notice that directories are a ilk of file. The key is that they own a specific ilk of format and contents (see Appendix B for more details). A directory holds the filenames and index numbers (see the following section, "Inodes") of bar nonexistent its constituent files, including subdirectories.

    Directory files are not flat (or regular) files, but are indexed (like a database), so that you can soundless locate a file quickly when you own a large number of files in the identical directory.13

    Even though file handling is generally transparent, it is considerable to recollect that a file's data blocks14 may not be stored sequentially (or even in the identical common disk region). When data blocks are widely scattered in an uncoordinated manner, it can influence access times and enlarge I/O overhead.

    Inodes

    Meta-information about files is stored in structures called index nodes, or inodes. Their contents vary based on the particular filesystem in use, but bar nonexistent inodes hold the following information about the file they index:15

  • Inode identification number

  • File type

  • Owners: user and group

  • UNIX permissions

  • File size

  • Timestamps

  • ctime: terminal file status change time

  • mtime: terminal data modification time16

  • atime: terminal access time

  • Reference/link count

  • Physical location information for data blocks

  • Notice that the filename is not stored in the inode, but as an entry in the file's closest parent directory.

    All other information about a file that ls displays is stored in an inode somewhere. With a few handy options, you can draw out lots of useful information. Let's relate that you want to know the inode number of the Solaris kernel.17 You just give the –i option, and voilá:

    [sun:10 ~]ls -i /kernel/genunix

    264206 genunix

    Of course, ls –l is an conventional friend, telling you most everything that you want to know. Looking at the Solaris kernel again, you score the output in device 3.4.

    Figure 3.4 Diagrammed Output of ls on a File

    Notice that the timestamp shown by default in a long listing is mtime. You can pass various options to ls to view ctime and atime instead. For other nifty permutations, contemplate the ls man page.

    File Permissions and Ownership Refresher

    Because UNIX was designed to back many users, the question naturally arises how to know who can contemplate what files. The first and simplest reply is simply to permit users to examine only their own files. This, of course, would beget it difficult, if not impossible, to share, creating much difficulties in collaborative environments and causing a string of other problems: Why can't I eschew ls? Because the system created it, not you, is only the most obvious specimen of such problems.

    Users and Groups

    UNIX uses a three-part system to determine file access: There's what you, as the file owner, are allowed to do; there's what the group is allowed to do; and there's what other people are allowed to do. Let's contemplate what Elvis's permissions contemplate like:

    [ elvis@frogbog elvis ]$ ls -l

    total 36

    drwxr-xr-x 5 elvis users 4096 Dec 9 21:55 Desktop

    drwxr-xr-x 2 elvis users 4096 Dec 9 22:00 Mail

    -rw-r--r-- 1 elvis users 36 Dec 9 22:00 README

    -rw-r--r-- 1 elvis users 22 Dec 9 21:59 ThisFile

    drwxr-xr-x 2 elvis users 4096 Dec 12 19:57 arc

    drwxr-xr-x 2 elvis users 4096 Dec 10 00:40 songs

    -rw-r--r-- 1 elvis users 46 Dec 12 19:52 tao.txt

    -rw-r--r-- 1 elvis users 21 Dec 9 21:59 thisfile

    -rw-r--r-- 1 elvis users 45 Dec 12 19:52 west.txt

    As long as we're here, let's fracture down exactly what's being displayed. First, they own a 10-character string of letters and hyphens. This is the representation of permissions, which I'll fracture down in a minute. The second detail is a number, usually a unique digit. This is the number of arduous links to that directory. I'll contend this later in this chapter. The third thing is the username of the file owner, and the fourth is the cognomen of the file's group. The fifth column is a number representing the size of the file, in bytes. The sixth contains the date and time of terminal modification for the file, and the final column shows the filename.

    Every user on the system has a username and a number that is associated with that user. This number generally is referred to as the UID, short for user ID. If a user has been deleted but, for some reason, his files remain, the username is replaced with that user's UID. Similarly, if a group is deleted but soundless owns files, the GID (group number) shows up instead of a cognomen in the group field. There are likewise other circumstances in which the system can't correlate the cognomen and the number, but these should be relatively rare occurrences.

    As a user, you can't change the owner of your files: This would open up some grave security holes on the system. Only root can chown files, but if he makes a mistake, you can now ask root to chown the files to you. As a user, you can chgrp a file to a different group of which you are a member. That is, if Elvis is a member of a group named users and a group named elvis, he can chgrp elvis west.txt or chgrp users west.txt, but because he's not a member of the group beatles, he can't chgrp beatles west.txt. A user can belong to any number of groups. Generally (although this varies a bit by flavor), files created belong to the group to which the directory belongs. On most modern UNIX variants, the group that owns files is whatever group is listed as your primary group by the system in the /etc/passwd file and can be changed via the newgrp command. On these systems, Elvis can chgrp users if he wants his files to belong to the users group, or he can chgrp elvis if he wants his files to belong to the elvis group.

    Reading Permissions

    So, what were those silly strings of letters and hyphens at the birth of each long directory listing? I already said that they represented the permissions of the file, but that's not especially helpful. The 10 characters of that string limn the authorization bits for each file. The first character is separate, and the terminal nine are three very similar groups of three characters. I'll account for each of these in turn.

    If you contemplate back to Elvis's long listing of his directory, you'll contemplate that most of the files simply own a hyphen as the first character, whereas several possess a d in this field. The more astute reader might note that the files with a d in that first field bar nonexistent betide to be directories. There's a pleasurable judgement for this: The first permissions character denotes whether that file is a special file of one sort or another.

    What's a special file? It's either something that isn't really a file (in the sense of a sequential stream of bytes on a disk) but that UNIX treats as a file, such as a disk or a video display, or something that is really a file but that is treated differently. A directory, by necessity, is a stream of bytes on disk, but that d means that it's treated differently.

    The next three characters limn what the user who owns the file can conclude with it. From left to right, these permissions are read, write, and execute. Read authorization is just that—the capability to contemplate the contents of a file. Write authorization implies not only the birthright to change the contents of a file, but likewise the birthright to delete it. If I conclude not possess write authorization to a file, rm not_ permitted.txt fails.

    Execute authorization determines whether the file is likewise a command that can be eschew on the system. Because UNIX sees everything as a file, bar nonexistent commands are stored in files that can be created, modified, and deleted devotion any other file. The computer then needs a course to recount what can and can't be run. The execute bit does this.

    Another considerable judgement that you requisite to worry about whether a file is executable is that some programs are designed to be eschew only by the system administrator: These programs can modify the computer's configuration or can be unsafe in some other way. Because UNIX enables you to specify permissions for the owner, the group, and other users, the execute bit enables the administrator to restrict the exhaust of unsafe programs.

    Directories treat the execute authorization differently. If a directory does not own execute permissions, that user (or group, or other users on the system) can't cd into that directory and can't contemplate at information about the files in that directory. (You usually can find the names of the files, however.) Even if you own permissions for the files in that directory, you generally can't contemplate at them. (This varies a bit by platform.)

    The second set of three characters is the group permissions (read, write, and execute, in that order), and the final set of three characters is what other users on the system are permitted to conclude with that file. Because of security concerns (either due to other users on your system or due to pervasive networks such as the Internet), giving write access to other users is highly discouraged.

    Changing Permissions

    Great, you can now read the permissions in the directory listing, but what can you conclude with them? Let's relate that Elvis wants to beget his directory readable only by himself. He can chmod go-rwx ~/songs: That means remove the read, write, and execute permissions for the group and others on the system. If Elvis decides to let Nashville artists select a contemplate at his material but not change it (and if there's a group nashville on the system), he can first chgrp nashville songs and then chmod g+r songs.

    If Elvis does this, however, he'll find that (at least, on some platforms) members of group nashville can't contemplate at them. Oops! With a simple chmod g+x songs, the problem is solved:

    [ elvis@frogbog elvis ]$ ls -l

    total 36

    drwxr-xr-x 5 elvis users 4096 Dec 9 21:55 Desktop

    drwxr-xr-x 2 elvis users 4096 Dec 9 22:00 Mail

    -rw-r--r-- 1 elvis users 36 Dec 9 22:00 README

    -rw-r--r-- 1 elvis users 22 Dec 9 21:59 ThisFile

    drwxr-xr-x 2 elvis users 4096 Dec 12 19:57 arc

    drwxr-x--- 2 elvis nashvill 4096 Dec 15 14:21 songs

    -rw-r--r-- 1 elvis users 46 Dec 12 19:52 tao.txt

    -rw-r--r-- 1 elvis users 21 Dec 9 21:59 thisfile

    -rw-r--r-- 1 elvis users 45 Dec 12 19:52 west.txt

    Special Permissions

    In addition to the read, write, and execute bits, there exists special permissions used by the system to determine how and when to suspend the natural authorization rules. Any thorough understanding of UNIX requires an understanding of the setuid, setgid, and sticky bits. For natural system users, only a common understanding of these is necessary, and this discussion is thus brief. pleasurable documentation on this matter exists elsewhere for budding system administrators and programmers.

    setuid

    The setuid bit applies only to executable files and directories. In the case of executable programs, it means that the given program runs as though the file owner were running it. That is, xhextris, a variant on Tetris, has the following permissions on my system:

    -rwsr-xr-x

    1 games games 32516 May 18 1999 /usr/X11R6/bin/xhextris

    There's a pseudouser called games on the system, which can't be logged into and has no home directory. When the xhextris program executes, it can read and write to files that only the game's pseudouser normally would be permitted. In this case, there's a high-score file stored on the system that writeable only by that user. When Elvis runs the game, the system acts as though he were the user games, and thus he is able to store the high-score file. To set the setuid bit on a file, you can recount chmod to give it mode u+s. (You can contemplate of this as uid set, although this isn't technically accurate.)

    setgid

    The setgid bit, which stands for "set group id," works almost identically to setuid, except that the system acts as though the user's group is that of the given file. If xhextris had used setgid games instead of setuid games, the towering score would be writeable to any directory owned by the group games. It is used by the system administrator in ways fundamentally similar to the setuid permission.

    When applied to directories on Linux, Irix, and Solaris (and probably most other POSIX-compliant UNIX flavors as well), the setgid bit means that current files are given the parent directory's group rather than the user's primary or current group. This can be useful for, say, a directory for fonts built by (and for) a given program. Any user might generate the fonts via a setgid command that writes to a setgid directory. setgid on directories varies by platform; check your documentation. To set the setgid bit, you can recount chmod to exhaust g+s (gid set).

    sticky

    Although a file in a group or world-writeable directory without the sticky bit can be deleted by anyone with write authorization for that directory (user, group, or other), a file in a directory with the sticky bit set can be deleted only by either the file's owner or root. This is particularly useful for creating temporary directories or scratch space that can be used by anyone without one's files being deleted by others. You can set authorization +t in chmod to give something the sticky bit.

    Numeric Permissions

    Like almost everything else on UNIX, permissions own a number associated with them. It's generally considered that permissions are a group of four digits, each between 0 and 7. Each of those digits represents a group of three permissions, each of which is a yes/no answer. From left to right, those digits limn special permissions, user permissions, group permissions, and other permissions.

    So, About Those authorization Bits...

    Most programs reading authorization bits expect four digits, although often only three are given. Shorter numbers are filled in with leading zeros: 222 is treated as 0222, and 5 is treated as 0005. The three rightmost digits are, as previously mentioned, user (owner) permissions, group permissions, and other permissions, from birthright to left.

    Each of these digits is calculated in the following manner: read authorization has a value of 4, write authorization has a value of 2, and execute authorization has a value of 1. Simply add these values together, and you've got that authorization value. Read, write, and execute would be 7, read and write without execute would be 6, and no authorization to conclude anything would be 0. Read, write, and execute for the file owner, with read and execute for the group and nothing at bar nonexistent for anyone else, would be 750. Read and write for the user and group, but only read for others, would be 664.

    The special permissions are 4 for setuid, 2 for setgid, and 1 for sticky. This digit is prepended to the three-digit numeric permission: A temporary directory with sticky read, write, and execute authorization for everyone would be mode 1777. A setuid root directory writeable by nobody else would be 4700. You can exhaust chmod to set numeric permissions directly, as in chmod 1777 /tmp.

    umask

    In addition to a more precise exhaust of chmod, numeric permissions are used with the umask command, which sets the default permissions. More precisely, it "masks" the default permissions: The umask value is subtracted from the maximum workable settings.* umask deals only with the three-digit permission, not the full-fledged four-digit value. A umask of 002 or 022 is most commonly the default. 022, subtracted from 777, is 755: read, write, and execute for the user, and read and execute for the group and others. 002 from 777 is 775: read, write, and execute for the user and group, and read and execute for others. I watch to set my umask to 077: read, write, and execute for myself, and nothing for my group or others. (Of course, when working on a group project, I set my umask to 007: My group and I can read, write, or execute anything, but others can't conclude anything with their files.)

    You should note that the umask assumes that the execute bit on the file will be set. bar nonexistent umasks are subtracted from 777 rather than 666, and those extra ones are subtracted later, if necessary. (See Appendix B for more details on authorization bits and umask workings.)

    *Actually, the authorization bits are XORed with the maximum workable settings, if you're a computer science type.

    Also notice that the first bit of output prepended to the permissions string indicates the file type. This is one handy course of identifying a file's type. Another is the file command, as shown in Table 3.3.

    Table 3.3 ls File Types and file Output Sample

    File Type

    ls File ilk Character

    File array Example

    Directory

    d

    [either:1 ~]file /usr/usr: directory

    Block special device

    b

    [linux: 10 ~] file /dev/hda1/dev/hda1: obstruct special (3/1)[sun:10 root ~]file /dev/dsk/c0t0d0s0/dev/dsk/c0t0d0s0: obstruct special(136/0)

    Character special device

    c

    [linux:11 ~] file /dev/tty0/dev/tty0: character special (4/0)

    [ensis:11 ~]file /dev/rdsk/c0t0d0s0/dev/rdsk/c0t0d0s0: character special (136/0)

    UNIX domain socket

    s

    [linux:12 ~] file /dev/log/dev/log: socket

    [sun:12 ~]file /dev/ccv/dev/ccv: socket

    Named pipe special (FIFO device)

    p

    [linux:13 ~] file /dev/initctl/dev/initctl: fifo (named pipe)

    [sun:13 ~]file /etc/utmppipe/etc/utmppipe: fifo

    Symbolic link

    l

    [linux:14 ~] file /usr/tmp/usr/tmp: symbolic link to ../var/tmp

    [sun:14 ~]file -h /usr/tmp/usr/tmp: symbolic link to ¬../var/tmp

    Regular

    -

    [linux:15 ~] file /etc/passwd/etc/passwd: ASCII text

    [linux:15 ~] file /boot/vmlinux-2.4.2-2/boot/vmlinux-2.4.2-2: ELF 32-bit LSB executable,

    ¬Intel 80386, version 1,statically linked, not stripped

    [linux:15 ~] file /etc/rc.d/init.d/sshd/etc/rc.d/init.d/sshd: Bourne-Again shell script text executable

    [sun:15 ~]file /etc/passwd

    /etc/passwd: ascii text

    [sun:15 ~]file /kernel/genunix

    -/kernel/genunix: ELF 32-bit MSB relocatable

    ¬SPARC Version 1

    [sun:15 ~]file /etc/init.d/sshd

    /etc/init.d/sshd: executable

    ¬/sbin/sh script

    Notice the in-depth information that file gives—in many cases, it shows details about the file that no other command will readily array (such as what kindhearted of executable the file is). These low-level details are beyond the scope of their discussion, but the man page has more information.

    Important Points about the file ommand

    file tries to device out what ilk a file is based on three types of test:

  • The file ilk that the ls –l command returns.

  • -The presence of a magic number at the birth of the file identifying the file type. These numbers are defined in the file /usr/share/magic in Red Hat Linux 7.1 and /usr/lib/locale/locale/LC_MESSAGES/magic (or /etc/magic) in Solaris 8. Typically, only binary files will own magic numbers.

  • -In the case of a regular/text file, the first few bytes are tested to determine the ilk of text representation and then to determine whether the file has a recognized purpose, such as C code or a Perl script.

  • file actually opens the file and changes the atime in the inode.

    Inode lists are maintained by the filesystem itself, including which ones are free for use. Inode allocation and manipulation is bar nonexistent transparent to both sysadmins and users.

    Inodes become significant at two times for the sysadmin: at filesystem creation time and when the filesystem runs out of free inodes. At filesystem creation time, the total number of inodes for the filesystem is allocated. Although they are not in use, space is set aside for them. You cannot add any more inodes to a filesystem after it has been created. When you eschew out of inodes, you must either free some up (by deleting or touching files) or migrate to another, larger filesystem.

    Without inodes, files are just a random assortment of ones and zeros on the disk. There is no guarantee that the file will be stored sequentially within a sector or track, so without an inode to point the course to the data blocks, the file is lost. In fact, every file is uniquely identified by the combination of its filesystem cognomen and inode number.

    See Appendix B for more circumstantial information on the exact content of inodes and their structure.

    Linux has a very useful command called stat that dumps the contents of an inode in a tidy format:

    [linux:9 ~]stat . File: "." Size: 16384 Filetype: Directory Mode: (0755/drwxr-xr-x) Uid: (19529/ robin) Gid:(20/users) Device: 0,4 Inode: 153288707 Links: 78 Access: Sun Jul 22 13:58:29 2001(00009.04:37:59) Modify: Sun Jul 22 13:58:29 2001(00009.04:37:59) Change: Sun Jul 22 13:58:29 2001(00009.04:37:59) Boot obstruct and Superblock

    When a filesystem is created, two structures are automatically created, whether they are immediately used or not. The first is called the boot block, where boot-time information is stored. Because a partition may be made bootable at will, this structure needs to be available at bar nonexistent times.

    The other structure, of more interest here, is the superblock. Just as an inode contains meta-information about a file, a superblock contains metainformation about a filesystem. Some of the more faultfinding contents are listed here:18

  • Filesystem name

  • Filesystem size

  • Timestamp: terminal update

  • Superblock status flag

  • Filesystem status flag: clean, stable, active

  • Number of free blocks

  • List of free blocks

  • Pointer to next free block

  • Size of inode list

  • Number of free inodes

  • List of free inodes

  • Pointer to next free inode

  • Lock fields for free blocks and inodes

  • Summary data block

  • And you thought inodes were complex.

    The superblock keeps track of free file blocks and free inodes so that the filesystem can store current files. Without these lists and pointers, a long, sequential search would own to be performed to find free space every time a file was created.

    In much the identical course that files without inodes are lost, filesystems without intact superblocks are inaccessible. That's why there is a superblock status flag—to bespeak whether the superblock was properly and completely updated before the disk (or system) was terminal taken offline. If it was not, then a consistency check must be performed for the all filesystem and the results stored back in the superblock.

    Again, more circumstantial information about the superblock and its role in UNIX filesystems may be found in Appendix B.

    Filesystem Types

    Both Red Hat and Solaris recognize a legion of different filesystem types, although you will generally cessation up using and supporting just a few. There are three benchmark types of filesystem—local, network, and pseudo—and a fourth "super-filesystem" ilk that is actually losing ground, given the size of modern disks.

    Local Filesystems

    Local filesystems are common to every system that has its own local disk.19 Although there are many instances of this ilk of filesystem, they are bar nonexistent designed to drudgery within a system, managing the components discussed in the terminal section and interfacing with the physical drive(s).

    Only a few local filesystems are specifically designed to be cross-platform (and sometimes even cross–OS-type). They Come in handy, though, when you own a nondisk hardware failure; you can just select the disk and build it into another machine to retrieve the data.20 The UNIX File System, or ufs, was designed for this; both Solaris and Red Hat Linux machines can exhaust disks with this filesystem. Note that Solaris uses ufs filesystems by default. Red Hat's default local filesystem is ext2.

    Another local, cross-platform filesystem is ISO9660, the CD-ROM standard. This is why you can read your Solaris CD in a Red Hat box's reader.

    Local filesystems Come in two related but discrete flavors. The original, benchmark model filesystem is soundless in broad exhaust today. The newer journaling filesystem ilk is just birth to really Come into its own. The major dissimilarity between the two types is the course they track changes and conclude integrity checks.

    Standard Filesystems

    Standard, nonjournaling filesystems rely on flags in the superblock for consistency regulation. If the superblock flag is not set to "clean," then the filesystem knows that it was not shut down properly: not bar nonexistent write buffers were flushed to disk, and so on. Inconsistency in a filesystem means that allocated inodes could be overwritten; free inodes could be counted as in use—in short, rampant file corruption, mass hysteria.

    But there is a filesystem integrity checker to redeem the day: fsck. This command is usually invoked automatically at boot-time to verify that bar nonexistent filesystems are immaculate and stable. If the / or /usr filesystems are inconsistent, the system might prompt you to start up a miniroot shell and manually eschew fsck. A few of the more faultfinding items checked and corrected are listed here:

  • Unclaimed blocks and inodes (not in free list or in use)

  • Unreferenced but allocated blocks and inodes

  • Multiply claimed blocks and inodes

  • Bad inode formats

  • Bad directory formats

  • Bad free obstruct or inode list formats

  • Incorrect free obstruct or inode counts

  • Superblock counts and flags

  • Note that a filesystem should be unmounted before running fsck (see the later section "Administering Local Filesystems"). Running fsck on a mounted filesystem might judgement a system panic and crash, or it might simply spurn to eschew at all. It's likewise best, though not required, that you eschew fsck on the raw device, when possible. contemplate the man page for more details and options.

    So where does fsck build orphans, the blocks and inodes that are clearly in exhaust but aren't referenced anywhere? Enter the lost+found directories. There is always a /lost+found directory on every system; other directories accrue them as fsck finds orphans in their purview. fsck automatically creates the directories as needed and renames the lost blocks into there by inode number. contemplate the man pages "mklost+found" on Red Hat and "fsck_ufs" on Solaris.

    Journaling Filesystems

    Journaling filesystems conclude away with fsck and its concomitant superblock structures. bar nonexistent filesystem status information is internally tracked and monitored, in much the identical course that databases systems set up checkpoints and self-verifications.

    With journaling filesystems, you own a better casual of replete data recovery in the event of a system crash. Even unsaved data in buffers can be recovered thanks to the internal log.21 This kindhearted of failing tolerance makes journaling filesystems useful in high- availability environments.

    The drawback, of course, is that when a filesystem devotion this gets corrupted somehow, it presents major difficulties for recovery. Most journaling filesystems provide their own salvaging programs for exhaust in case of emergency. This underscores how faultfinding backups are, no matter what kindhearted of filesystem software you've invested in. contemplate Chapter 16, "Backups," for more information.

    One of the earliest journaling filesystems is soundless a commercial venture: VxFS by Veritas. Another pioneer has decided to release its software into the public domain under GPL22 licensing: JFS23 by IBM. SGI's xfs journaling filesystem has been freely available under GPL since about 1999, although it is only designed to drudgery under IRIX and Linux.24

    Maintenance of filesystem status incurs an overhead when using journaling filesystems. As a result, these filesystems execute suboptimally for minuscule filesystem sizes. Generally, journaling filesystems are commandeer for filesystem sizes of 500Mb or more.

    Network Filesystems

    Network-based filesystems are really add-ons to local filesystems because the file server must own the actual data stored in one of its own local filesystems.25 Network file- systems own both a server and client program.

    The server usually runs as a daemon on the system that is sharing disk space. The server's local filesystems are unaffected by this extra process. In fact, the daemon generally only puts a few messages in the syslog and is otherwise only visible through ps.

    The system that wants to access the server's disk space runs the client program to mount the shared filesystems across the network. The client program handles bar nonexistent the I/O so that the network filesystem behaves just a devotion a local filesystem toward the client machine.

    The conventional standby for network-based filesystems is the Network File System (NFS). The NFS benchmark is currently up to revision 3, though there are quite a number of implementations with their own version numbers. Both Red Hat and Solaris Come benchmark with NFS client and server packages. For more details on the inner workings and configuration of NFS, contemplate Chapter 13, "File Sharing."

    Other network-based filesystems comprehend AFS (IBM's Andrew File System) and DFS/DCE (Distributed File System, section of the Open Group's Distributed Computing Environment). The mechanisms of these advanced filesystems travel beyond the scope of this book, although their goal is soundless the same: to efficiently share files across the network transparently to the user.

    Pseudo Filesystems

    Pseudofilesystems are an entertaining development in that they are not actually related to disk-based partitions. They are instead purely ratiocinative constructs that limn information and meta-information in a hierarchical structure. Because of this structure and because they can be manipulated with the mount command, they are soundless referred to as filesystems.

    The best specimen of pseudofilesystems exists on both Red Hat and Solaris systems: /proc. Under Solaris, /proc is restricted to just managing process information:

    [sun:1 ~]ls /proc 0 145 162 195 206 230 262 265 272 286 299 303 342 370 403 408 _672 752 1 155 185 198 214 243 263 266 278 292 3 318 360 371 404 52 _674 142 157 192 2 224 252 264 268 280 298 302 319 364 400 406 58 _678

    Note that these directories are bar nonexistent named according to the process numbers corresponding to what you would find in the output of ps. The contents of each directory are the various meta-information that the system needs to manage the process.

    Under Red Hat, /proc provides information about processes as well as about various system components and statistics:

    [linux:1 ~] ls /proc 1 18767 23156 24484 25567 28163 4 493 674 8453 ksyms _stat 13557 18933 23157 24486 25600 3 405 5 675 9833 loadavg _swaps 13560 18934 23158 24487 25602 3050 418 5037 676 9834 locks _sys 13561 18937 23180 24512 25603 3051 427 5038 7386 9835 mdstat _tty 1647 19709 23902 24541 25771 3052 441 5054 7387 bus meminfo _uptime 1648 19730 23903 24775 25772 30709 455 5082 7388 cmdline misc _version 1649 19732 23936 25494 25773 30710 473 510 7414 cpuinfo modules 16553 19733 24118 25503 25824 30712 485 5101 7636 devices mounts 18658 2 24119 25504 25882 30729 486 524 7637 dma mtrr 18660 21450 24120 25527 25920 320 487 558 7638 filesystems net 18661 21462 24144 25533 26070 335 488 6 7662 fs _partitions 18684 21866 24274 25534 26071 337 489 670 8426 interrupts pci 18685 21869 24276 25541 26072 338 490 671 8427 ioports scsi 18686 21870 24277 25542 28161 339 491 672 8428 kcore self 18691 21954 24458 25543 28162 365 492 673 8429 kmsg slabinfo

    Again they contemplate the directories named for process numbers, but they likewise contemplate directories with indicative names such as cpuinfo and loadavg. Because this is a hierarchical filesystem, you can cd into these directories and read the various files for their system information.

    The most entertaining thing about /proc is that it allows even processes to be treated devotion files.26 This means that pretty much everything in UNIX, whether it is something that just exists or something that actually happens, can now be considered a file.

    For more information under Red Hat, ilk man proc. For more information under Solaris, ilk man –s 4 proc.

    Logical Volumes

    Finally, there are the "super-filesystems" or ratiocinative volumes that conclude what the other major types of filesystem cannot: surmount the barriers of partitions. You may well ask why anyone would want to conclude that. There are two reasons. First, because disks used to be a lot smaller and more costly, you used what you had at hand. If you needed a large pool of disk space, ratiocinative volumes allowed you to aggregate remnants into something useable. Second, even with larger disks, you soundless might not be able to achieve the kindhearted of disk space required by a particular researcher or program. Once again, ratiocinative volumes allow you to aggregate partitions across disks to profile one large filesystem.

    Crossing disk boundaries with a ratiocinative volume is referred to as disk spanning. Once you own ratiocinative volumes, you can likewise own some fairly complicated data management methods and performance-enhancing techniques. Disk striping, for example, is a performance booster. Instead of sequentially filling one disk and then the next in series, it spreads the data in discrete chunks across disks, allowing better I/O response through parallel operations.

    RAID27 implements ratiocinative volumes at 10 discrete levels, with various features at each level. This implementation can be done either in hardware or in software, although the nomenclature for both is the same.28

    Table 3.4 RAID Levels

    RAID Level

    Features

    Implications

    0

    Disk striping

    Fastest

    Not self-repairing

    1

    Disk mirroring

    Fast

    Self-repairing

    -Requires extra drives for data duplication

    2

    Disk striping

    Fast

    Error correction

    Self-repairing

    (Very similar to RAID-3)

    3

    Disk striping

    Slower

    Parity disk

    Self-repairing

    Error correction

    Requires part parity disk

    4

    Disk striping

    Slower

    Parity disk

    Self-repairing

    Requires part parity disk

    (Very similar to RAID-5)

    5

    Disk striping

    Slowest for writes, but

    Rotating parity array

    good for reads

    Self-repairing

    Requires three to five part parity disks

    Reconstruction by parity data (not duplication)

    6

    RAID-5 + secondary

    Not in broad use

    parity scheme

    7

    RAID-5 + real-time embedded controller

    Not in broad use

    0+1

    Mirrored striping

    -RAID-0 array duplicated (mirrored)

    1+0

    Striped mirroring

    -Each stripe is RAID-1 (mirrored) array

    High cost

    0+3

    Array of parity stripes

    Each stripe is RAID-3 array

    High cost

    Clearly, the kindhearted of complexity inherent in bar nonexistent ratiocinative volume systems requires some kindhearted of back-end management system. Red Hat offers the ratiocinative Volume Manager (LVM) as a kernel module. While the details of LVM are beyond the scope of this book, it is entertaining to note that you can build any filesystem that you want on top of the ratiocinative volume. Start at http://www.linuxdoc.org/HOWTO/LVM-HOWTO.htmlfor more details.

    Although Sun offers ratiocinative volume management, it is through a for-pay program called "Solstice DiskSuite." The filesystem on DiskSuite ratiocinative volumes must be ufs. For more information, start at http://docs.sun.com/ab2/coll.260.2/DISKSUITEREF.

    Another commercial ratiocinative volume manager for Solaris comes from Veritas; see: http://www.veritas.com/us/products/volumemanager/faq.html#a24

    The beauty of bar nonexistent ratiocinative volumes is that they loom to be just another local filesystem and are completely transparent to the user. However, ratiocinative volumes conclude add some complexity for the systems administrator, and the schema should be carefully documented on paper, in case it needs to be re-created.

    NAS

    Normally, a file server's disks are directly attached to the file server. With network-attached storage (NAS), the file server and the disks that it serves are part entities, communicating over the local network. The storage disks require an aggregate controller that arbitrates file I/O requests from the external server(s). The server(s) and the aggregate controller each own discrete network IP addresses. To serve the files to clients, a file (or application) server sends file I/O requests to the NAS aggregate controller and relays the results back to client systems.

    NAS is touched on here for completeness—entire books can be written about NAS design and implementation. NAS does not really limn a ilk of filesystem, but rather it is a mechanism to alleviate the file server from the details of hardware disk access by isolating them in the network-attached storage unit.

    Red Hat Filesystem Reference Table

    Table 3.5 lists major filesystems that currently back (or are supported by) Red Hat.29 The filesystem types that are currently natively supported are listed in /usr/src/linux/ fs/filesytems.c.

    Table 3.5 Filesystem Types and Purposes, with Examples (Red Hat)

    Filesystem Type

    Specific Instances (as Used in /etc/fstab)

    Purpose

    Local

    ext2

    Red Hat default filesystem

    ufs

    Solaris compatibility

    jfs

    Journaling filesystem from IBM

    xfs

    Journaling filesystem from SGI

    msdos

    Windows compatibility: DOS

    ntfs

    Windows compatibility: NT

    vfat

    Windows compatibility: FAT-32

    sysv

    SYS-V compatibility

    iso9660

    CD-ROM

    Adfs hfs romfs

    Others

    Affs hpfs smbfs

    Coda mnix udf

    devpts ncpfs umsdos

    efs qux4

    coherent

    Deprecated, pre-kernel 2.1.21

    ext

    xenix

    xiafs

    Network

    afs

    Network-based remote communication

    autofs

    nfs

    Pseudo

    proc

    Store process (and other system) meta-information

    Solaris Filesystem Reference Table

    Table 3.6 lists major filesystems that currently back (or are supported by) Solaris. The filesystem types that currently are natively supported are listed as directories under /usr/lib/fs.

    Table 3.6 Filesystem Types and Purposes, with Examples (Solaris)

    Filesystem Type

    Specific Instances (as Used in /etc/vfstab)

    Purpose

    Local

    ufs

    Solaris default filesystem; Red Hat-compatible

    pcfs

    PC filesystem

    hsfs

    CD-ROM

    jfs

    Journaling filesystem from IBM

    Network

    afs

    Network-based remote communication

    nfs

    Pseudo

    procfs

    Store process metainformation

    Fdfs swapfs tmpfs

    Mount metainformation areas as filesystems

    mntfs cachefs lofs

    fifofs specfs udfs namefs



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    References :












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