Tivoli Storage Manager transaction sizes

For Tivoli® Storage Manager configurations, the TXNGROUPMAX option specifies the number of objects that can be transferred between a client and the server in one backup transaction. The maximum value is 65000. The default value is 256 objects. If the value is too low, your backups can fail with a start a new transaction session error.

If you encounter this error, review and increase the TXNGROUPMAX setting to a value that is larger than the maximum number of objects that a single backup operation will try to create. For example, if you are performing incremental backups, then use a value that is at least twice the table count. Also, add a small number (such as five) of additional objects for backup metadata files. If your database has UDXs, add an additional two objects for each UDX. If you are using multi-stream backups, then use the maximum value of either double the UDXs, or double the tables divided by the stream count, and add the additional five objects for metadata objects.

To set the TXNGROUPMAX value by using the GUI, go to the Policy Domains and Client Nodes > Your client node > Advanced Settings > Maximum size of a transaction. The options are Use server default or Specify a number (4-65,000). If you choose Specify a number, the setting cannot be changed from the client. If you chose Use server default, you can specify the value from the clients by using the dsmadmc application, 'setopt txngroupmax <value>' or 'update node txngroupmax=<value>'.