Storage area networks (SAN) deliver consolidated storage and advanced storage management features. One advanced SAN configuration involves booting servers directly from the SAN, eliminating all locally attached storage, and improving server operations. Several server boot options are available. To select the right boot option for your environment, you should weigh the benefits and drawbacks of each.
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ISCSI SAN BOOT - SIMPLIFYING SERVER OPERATIONS ON SANS
Three server boot operations Storage area networks (SAN) deliver consolidated storage and advanced storage man-offer different benefits: agement features. One advanced SAN configuration involves booting servers directly. Traditional boot: Easy to use, from the SAN, eliminating all locally attached storage, and improving server operations.basic functionality Several server boot options are available: 1) traditional boot from internal storage; 2) boot. Network boot: Complex to from a server on the network; and 3) boot from the iSCSI SAN. To select the right bootimplement, scales well option for your environment, you should weigh the benefits and drawbacks of each.. SAN boot: Simple process,advanced functionality, andscales well TRADITIONAL BOOT - SIMPLE OPERATION, SIMPLE FUNCTIONALITYThe conventional method of booting a server is from internal storage. At startup, the BIOSfinds boot information on the local hard drive and the operating system launches. Thissimple, one-step process functions in a manner that administrators understand well.
There are drawbacks to internal storage however - all the common problems of directattached storage. To add storage or service to a machine the administrator must shutdown (interrupting business tasks) and physically open the system. A disk failure typically eliminates all server functions. Each server requires more space, power andcooling because of the disk drives. Storage management is labor-intensive as administrators individually configure, backup, and manage each server. Most important,needed storage management features are missing.
NETWORK BOOT - MORE COMPLEX, USEFUL IN SERVERFARMS AND GRIDSSome operating systems support boot from NICs called PXE orDHCP/TFTP (depending on operating system). In environments withmany systems, management can be more efficient and affordable thanusing local devices. In addition, you can use servers without disks,which offer several benefits: 1) They cost less and take up less space,power and cooling; 2) Fewer components make them more reliable; and 3) Administrators can re-purpose servers, easily changing to meetapplication demands.
However, the network boot process is significantly different from typicalboot operation. For example, to network boot 20 application servers, the administratoris burdened with more setup tasks: an additional boot server on the network. Setupincludes building a "gold" master image on a machine similar to those you want to boot(on a local disk), copying that image to network storage, replicating system images,customizing replicas for each server, and configuring the boot SAN boot enhances server reliability and performance byserver to deliver the right image to each application server. leveraging the SAN for improved RAID operations. SAN bootalso delivers centralized storage management, and advancedBecause this method takes much more infrastructure and features such as disk image cloning, snapshots, and disastereffort, it is primarily used with large numbers of servers, as the replication. Now all of your data can be managed in a extra work can be "amortized." However, there are other consistent and efficient manner. You can easily re-purposedrawbacks. Because your application servers' boot process servers, and improve business continuity - if a server mal-depends on the boot server, it must be clustered or otherwise functions, you simply boot another server using the originalmade highly available, adding more management. Installing boot image and continue working. patches and software is more complicated, as each system alteration may also require updating the boot images CHOOSE YOUR BOOT METHOD WITH THE PS SERIES SANand re-imaging. While EqualLogic's PS Series array supports all three bootmethods, there are clear benefits to booting from the SAN.SAN BOOT - FAMILIAR EASY OPERATION, WITH These include improved server uptime; online servicing andADVANCED MANAGEMENT FEATURES management of storage on the SAN; and automatic, onlineYou can also boot servers directly from the SAN. You gain expansion and load balancing. You gain many needed the simple, natural operation of traditional boot, plus the hard- storage management functions, snapshot capability thatware cost reductions and... [download for more]