Chapter 14. Designing an N series solution 19914.2.8 Backup serversProtecting and archiving critical corporate data is increasingly important. Deploying serversfor this purpose is becoming more common, and these configurations call for their ownplanning guidelines.A backup server generally is not designed to deliver high transactional performance. Datacenter managers rely on the backup server being available to receive the backup streamswhen they are sent. Often, the backup server is an intermediate repository for data before itgoes to back up tape and ultimately offsite. However, the backup server frequently takes theplace of backup tapes.The write throughput of a backup server frequently is the most important factor to consider inplanning. Another important factor is the number of simultaneous backup streams that asingle server can handle. The more effective the write throughput and the greater the numberof simultaneous threads, the more rapidly backup processes complete. The faster theprocesses complete, the sooner that production servers are taken out of backup mode andreturned to full performance.Each IBM System Storage N series platform has different capabilities in each of these areas.The planning process must take these characteristics into account to ensure that the backupserver is capable of the workload expected.14.2.9 Backup and recoveryIn addition to backup servers, all storage systems must be backed up. Generally, the goal is tohave the backup process occur at a time and in a way that minimizes the effect on overallproduction. Therefore, many backup processes are scheduled to run during off-hours.However, all of these backups run more or less at the same time. Therefore, the greatest I/Oload that is put on the storage environment frequently is during these backup activities,instead of during normal production.IBM System Storage N series storage systems have a number of backup mechanismsavailable. With prior planning, you can deploy an environment that provides maximumprotection against failure while optimizing the storage and performance capabilities.The following issues must be considered: Storage capacity that is used by SnapshotsHow much extra storage must be available for Snapshots to use? Networking bandwidth that is used by SnapMirrorIn addition to the production storage I/O paths, SnapMirror needs bandwidth to duplicatedata to the remote server. Number of possible simultaneous SnapMirror threadsHow many parallel backup operations can be run at the same time before some resourceruns out? Resources to consider include processor cycles, network throughput, maximumparallel threads (which is platform-dependent), and the amount of data that requirestransfer. Frequency of SnapMirror operationsThe more frequently data is synchronized, the fewer the number of changes each time.More frequent operations result in background operations running almost all the time.
