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If one or more storage pool volumes is lost or damaged, the client data may be permanently lost. However, you can back up storage pools to sequential access copy storage pools and move the volumes offsite. If data is lost or damaged, you can restore individual volumes or entire storage pools from the copy storage pools. The server tries to access the file from a copy storage pool if the primary copy of the file cannot be obtained for one of the following reasons:
For details, see Restoring Storage Pools, Using Copy Storage Pools to Improve Data Availability, Recovering a Lost or Damaged Storage Pool Volume, and Maintaining the Integrity of Files.
Two commands let you restore files from copy storage pools:
Tivoli Storage Manager uses database information to determine which files should be restored for a volume or storage pool. As a result, restore processing does not require that the original volumes be accessed. For example, if a primary storage pool volume is damaged, you can use the RESTORE VOLUME command to recreate files that were stored on that volume, even if the volume itself is not readable. However, if you delete the damaged files (DISCARDDATA=YES on the DELETE VOLUME command), the server removes from the database references to the files on the primary storage pool volume and to copies of the files on copy storage pool volumes. You could not restore those files.
Restore processing copies files from a copy storage pool onto new primary storage pool volumes. The server then deletes database references to files on the original primary storage pool volumes. A primary storage pool volume will become empty if all files that were stored on that volume are restored to other volumes. In this case, the server automatically deletes the empty volume from the database.
The destroyed volume access mode permits the restoration of entire volumes. This mode designates primary volumes for which files are to be restored. If a volume is designated as destroyed, the server does not mount that volume for either read or write access. You can designate a volume as destroyed with either of two commands:
The destroyed designation for volumes is important during restore processing, particularly when the RESTORE STGPOOL command is used to restore a large number of primary storage pool volumes after a major disaster: