Tivoli Storage Manager for HP-UX Administrator's Guide


Storage Pool Protection: An Overview

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. TSM 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.

How Restore Processing Works

Two TSM commands let you restore files from copy storage pools:

RESTORE STGPOOL
Restores all storage pool files that have been identified as having read errors. These files are known as damaged files. This command also restores all files on any volumes that have been designated as destroyed by using the UPDATE VOLUME command. See Restoring Storage Pools for details.

RESTORE VOLUME
Recreates files that reside on a volume or volumes in the same primary storage pool. You can use this command to recreate files for one or more volumes that have been lost or damaged. See Restoring Storage Pool Volumes for details.

Because TSM uses database information to determine which files should be restored for a volume or storage pool; restore processing does not require that the original volumes be accessed. For example, if a primary storage pool volume is damaged, you could 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), TSM 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. TSM then deletes database references to files on the original primary storage pool volumes. If a primary storage pool volume becomes empty because all files that were stored on that volume have been restored to other volumes, TSM automatically deletes the empty volume from the database.

How the Destroyed Volume Access Mode Works

To help restore processing of entire volumes, TSM has a destroyed volume access mode. This mode designates primary volumes for which files are to be restored. If a volume is designated as destroyed, TSM 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:


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