Environment considerations

IBM Storage Protect performance depends upon the environment.

Consider sequential-access disk (FILE) to store data that requires quick restoration. For data that is less critical, store the data to random access disk, then allow or force the data to migrate to tape.

You can also use active-data pools to store active versions of client backup data. Archive and space-managed data is not allowed in active-data pools. Inactive files are removed from the active-data pool during expiration processing. Active-data pools that are associated with a FILE device class do not require tape mounts, and the server does not have to position past inactive files. In addition, FILE volumes can be accessed concurrently by multiple client sessions or server processes. You can also create active-data pools that use tape media, which can be moved off-site, but which require tape mounts.

If you do not use FILE or active-data pools, consider how restore performance is affected by the layout of data across single or multiple tape volumes. You can have multiple simultaneous sessions when you use FILE to restore, and mount overhead is skipped with FILE volumes. Major causes of performance problems are excessive tape mounts and needing to skip over expired or inactive data on a tape. After a long series of incremental backups, perhaps over years, the active data for a single file space can be spread across many tape volumes. A single tape volume can have active data that is mixed with inactive and expired data.