Tivoli Storage Manager for Sun Solaris Administrator's Guide
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:
- The primary file copy has been previously marked damaged (for information
about damaged files, see Correcting Damaged Files).
- The primary file is stored on a volume that UNAVAILABLE or
DESTROYED.
- The primary file is stored on an offline volume.
- The primary file is located in a storage pool that is UNAVAILABLE, and the
operation is for restore, retrieve, or recall of files to a user, or export of
file data.
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 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.
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:
- RESTORE VOLUME -- This command automatically changes the access mode
of specified volumes to the destroyed volume access mode using a volume list
provided as part of the command.
- UPDATE VOLUME -- Before using this command to restore volumes in a
storage pool, you must update the access mode of the volumes to
destroyed.
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:
- You can designate as destroyed only those volumes that need to be
restored. If some volumes are known to be usable after a disaster, the
access state of the usable volumes should not be set to destroyed, and
therefore they will not be restored as they are usable as they are.
- After you have identified the primary volumes to be restored and changed
their access mode to destroyed, you can add new volumes to the storage
pool. The new volumes are used to contain the files as they are
restored from the copy storage pool volumes. The new volumes can also
be used for new files that end users back up, archive, or migrate.
- The designation of destroyed volumes lets TSM track the files that must
still be restored from copy storage pools. If restore processing is
ended before completion for any reason, you can restart the restore.
Only the files that still reside on destroyed volumes would need to be
restored.
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