Tivoli Storage Manager Recovery Log –

Before V6, the recovery log was a single log storage structure that stored transaction data representing modifications such as insertion, update, or deletion of records for tables in the server database. Maximum Supported DB size is 13GB, but in real practice it is around 10 GB.

There were two considerations relating to how the recovery log worked and these were managed by the log mode for the server

It has 2 Modes –

• Normal Mode
• Roll Forward Mode 

• Normal Mode – There are certain system defined threshold, when the recovery log reaches those threshold it will be committed to database.
• Roll Forward – Here in case of roll forward we will define one threshold and when the recovery log reached that threshold, DB will start getting backed up. In Normal mode if DB crashed, we will be able to recover it for the last day or time when it was backed up.

But in real environment in both the cases we schedule DB backup.

After V6, With V6.1, V6.2, or V6.3 the recovery log is now comprised of two primary storage locations, for the active log and the archive log. There are additional, optional log storage locations, but the focus of this document is the two required storage locations.

• Active Log – Is used to store current in-flight transactions for the server.
• Archive Log – Is used as a storage repository for log files that were previously active and no longer contain references for in-flight transactions.

Click here for detailed information about log sizing on TSM v6.x and v7.1.