TSM: Why are backups going to tape instead of disk

Technote (troubleshooting)

Problem(Abstract)

Tivoli Storage Manager TSM Client backups and/or archives may go to a tape pool although the management class used sends data to a disk pool

Cause

DISK pool is not available or does not have free space or data size exceeds threshold.

Resolving the problem

TSM Client backups and/or archives are directed to particular storage pool via the "copy destination" field of the backup or archive copygroup of the management class used for the operation. For example, assuming the following backup copygroup settings for the below management class :


Policy Domain Name: STANDARD
Policy Set Name: active
Mgmt Class Name: UNIX
Copy Group Name: STANDARD
Copy Group Type: Backup
Copy Destination: BACKUPPOOL

And assuming the following configuration for the BACKUPPOOL storage pool :

Storage Pool Name: BACKUPPOOL
Storage Pool Type: Primary
Device Class Name: DISK
Estimated Capacity: 400.0 G
Maximum Size Threshold: 10G
Next Storage Pool: TAPEPOOL

A Tivoli Storage Management client using the above management class for a backup operation may back up the data directly to the TAPEPOOL instead of the BACKUPPOOL under the following conditions :

1. Backup data size exceeds 10GB.
2. If the client data ( file ) size is greater than 10GB, the backup of such data will go to TAPEPOOL directly. This is controlled by the "Maximum Size Threshold" parameter.
3. Backup data size exceeds BACKUPPOOL free space
4. If the client data size is greater than the BACKUPPOOL free space, or if the BACKUPPOOL storage pool is full, such backup will go to TAPEPOOL directly. Migration may be used to free up some space.
5. BACKUPPOOL is unavailable or readonly. Verify the access of the storage pool with "Q STG F=D" which must be readwrite and verify the BACKUPPOOL storage pool volumes are also online. Use the Q VOL F=D command to verify this.

Source: IBM Technote http://www-01.ibm.com/support/docview.wss?uid=swg21266633