About this task
You can write data simultaneously during any of the following
operations:
- Client store sessions, for example:
- Backup and archive sessions by Tivoli Storage
Manager backup-archive
clients.
- Backup and archive sessions by application clients using the Tivoli Storage
Manager API.
- Migration processes by hierarchical storage management (HSM) clients.
Migrated data is simultaneously written only to copy storage pools.
Migrated data is not permitted in active-data pools.
- Server migration of data within a storage pool hierarchy.
- Server import processes that involve copying exported file data
from external media to a primary storage pool that is configured for
the simultaneous-write function. Imported data is simultaneously written
to copy storage pools. Imported data is not simultaneously written
to active-data pools. To store newly imported data into an active-data
pool, use the COPY ACTIVEDATA command.
The maximum number of copy storage pools and active-data
pools to which data can be simultaneously written is three. For example,
you can write data simultaneously to three copy storage pools, or
you can write data simultaneously to two copy storage pools and one
active-data pool.
Attention: Do not use the simultaneous-write
function to replace the task of regularly backing up storage pools.
If you use the function to simultaneously write to copy storage pools,
active-data pools, or both, ensure that the copy of each primary storage
pool is complete by regularly issuing the BACKUP STGPOOL command
and the COPY ACTIVEDATA command. If you fail to
regularly back up storage pools. you can lose the ability to recover
primary storage pool data. For example, if a copy storage pool fails
during a write operation and the COPYCONTINUE parameter
is set to YES, the Tivoli Storage
Manager server removes
the failed copy storage pool from the copy pool list for the remainder
of the client session. After the copy storage pool is removed, the Tivoli Storage
Manager server continues
to write to the primary storage pool and to any remaining copy storage
pools and active-data pools. If these pools become damaged or lost,
and if you did not issue the BACKUP STGPOOL command
for the copy storage pool that failed, you might not be able to recover
your data.
Data that is simultaneously written to copy storage
pools or active-data pools during migration is not copied when primary
storage pools are backed up or when active data is copied.