OAM contains the Volume Recovery utility that recovers the objects
from an unusable optical or tape volume to a usable volume. The Volume
Recovery utility is used if an optical or tape volume is rendered
unreadable, either because of physical damage, or because the volume
cannot be found. The Volume Recovery utility is used for two types
of volume recovery:
- Volumes containing primary objects belonging to an Object storage
group can be recovered from the first or second backup copies of the
objects (optical or tape).
- Backup volumes belonging to an Object Backup storage group can
be recovered from the primary copies of the objects (disk (DB2 or
file system), optical, or tape). All storage groups that contain objects
that need to be recovered must be defined as part of the ACDS configuration.
To recover a primary optical or tape volume, all of the backup
volumes containing either the first or the second backup copies of
the objects on the primary volume are needed, whether they are optical
or tape. The media from which the backup copy is retrieved for the
recovery depends on the volume on which the selected backup copy resides.
If you specified the DELETE option, you can delete recovered tape
and optical volumes after all data on those volumes has been recovered
successfully.
Example: OAM might have run one storage management
cycle for the storage group after OAM was initialized with a CBROAM
xx PARMLIB member that contained a particular SETOAM statement.
This SETOAM statement specified a tape unit name for an Object Backup
storage group that caused OAM to write backups for that group to tape.
Another time, OAM might have run a storage management cycle for the
storage group after OAM was initialized, and the system invoked the
START OAM command with one of these three options:
- Without a CBROAMxx PARMLIB member
- With a CBROAMxx PARMLIB member that contained no SETOAM
statements
- With a SETOAM statement that did not specify a tape unit name
that was associated with an Object Backup storage group
Any one of these options causes OAM to write backups to an optical
volume.
When recovering a backup volume, every Object storage group must
be searched for primary objects having backup copies residing on the
backup volume being recovered. The primary copy for each of these
objects can be on disk (DB2 or file system), optical, or tape. As
a result, the Volume Recovery utility must identify the optical volumes
as well as the tape volumes that are needed for recovery. If both
optical and tape volume are requested for the recovery, the operator
must reply that both types are available for the recovery to continue.
The operator starts the recovery utility to copy the data.
The Volume Recovery operation is similar to that of Movevol, and,
as such, it's performance can also be enhanced by employing the same
techniques used to tune the Movevol environment. Refer to Analyzing resources and tuning OAM for MOVEVOL usage.
For more information on the Volume Recovery utility, see Starting the OAM Volume Recovery utility and Stopping a volume recovery that is in progress.