Dell Power Solutions

STORAGEBackup concepts, while firmly rooted in the IT mind-set, continueto evolve as technology advances. In the process, backups takeon new meaning and organizations develop innovative approachestoward implementing such procedures. Although sometimes deliveredas a stand-alone solution, disaster recovery is more often consideredto be a component of a backup and recovery solution. Putsimply, disaster recovery can be defined as the capability to quicklyand gracefully recover from total data loss. However, this definitionhas become blurred in the midst of the many cluster, replication, andother availability products that are being developed and promotedas disaster recovery solutions.Manual recovery processes: Time-consuming and inefficientWhen compared to the reality of data loss, even a manual recoveryprocess is better than no recovery at all. According to recent pollsconducted by Yosemite, 1 up to one-quarter of the midsize businessespolled plan to use manual recovery as their approach for disasterrecovery. However, manually recovering a failed system can proverather cumbersome and time-consuming for even the most seasonedIT professionals.Whether the system failure and resulting data loss is on ane-commerce server, an accounting system devoted to payroll, ora file server full of architectural drawings, the first task after aserver failure is to isolate the problem that caused the failureand take steps to correct it. Doing so can be as simple as identifyingand replacing a defective SCSI controller and hard drive,or as difficult as finding a replacement for an obsolete motherboard.Administrators must then configure hard drive partitionsand any special RAID sets that are needed, and once the basichardware problems are resolved, they must locate the relevantinstallation CDs and license activation keys. Next, administratorsmust reinstall the OS. Previous system information such asnetwork addresses, directory structures, volume sizes, and clusterdata may be needed to complete the installation. In a best-casescenario, the server that is being recovered will have Internetaccess, because the OS and any special hardware configurationmay require device drivers, patches, and service packs to restoreaccess to the system’s peripherals.Once the base OS is up and running, administrators need tolocate, install, and configure the server’s applications and backupsoftware. Typically, after hours of manual processes, administratorscan finally insert a tape and start rebuilding the catalog so that theycan begin selecting files to restore. Depending on the server’s configuration,this catalog rebuild and restore process can consume evenmore time than the hours already spent on recovery. See Figure 1for an example of efficient recovery using an automated bare-metalprocess versus a typical disaster recovery process.PlanningPlanning10:00 A.M.11:00 A.M.12:00 P.M.1:00 P.M.2:00 P.M.3:00 P.M.4:00 P.M.5:00 P.M.6:00 P.M.7:00 P.M.Figure 1. Recovery using an automated bare-metal process versus a typical disaster recovery processAutomated bare-metal disaster recoveryThe benefit of bare-metal disaster recovery derives from the capabilityto automatically re-create hard drive partitions and perform a fullsystem recovery of the OS, applications, and data. This capabilityalone has the potential to shorten a typical manual recovery processby several hours. Two steps are required to prepare for the disasterrecovery process:Automatedbare-metal processDisasterrecovery setupDaily/weeklybackupsData losseventReplace/repairhardwareInsert boot media/restore dataSystemrecovered• Make a full backup of the system exactly as it should berestored in the event of a disaster.• Create the appropriate boot media.The full backup is used with appropriate boot media—eitherbootable floppy disks, a bootable CD image, or a bootable tapedevice—to perform a complete restoration. Disaster recoveryproducts are designed to be as automated as possible during bothpreparation and recovery phases, so that once installed, a disasterrecovery product should be able to perform its tasks with minimalhands-on intervention.Typical disasterrecovery processDisasterrecovery setupDaily/weeklybackupsData losseventReplace/repairhardwareInsert boot media/launch recoveryRestoredataSystemrecoveredManual disasterrecovery processDaily/weeklybackupsData losseventReplace/repairhardwareReinstalloperating systemReinstallservice packsReinstallapplicationsReinstall backupsoftwareRebuild/catalogtape indexCreate/launchrestore jobRestoredataSystemrecoveredNote: Recovery time examples represent system tests performed in Microsoft® Windows Server 2003 environments.Actual recovery time will vary based on hardware configuration and data volume.1In September to December 2004, Yosemite conducted polls of midsize companies that were not current Yosemite customers.80POWER SOLUTIONS Reprinted from Dell Power Solutions, February 2005. Copyright © 2005 Dell Inc. All rights reserved. February 2005