17. Backing Up and Restoring the Database : Recovery from Checkpoints : Recover from the Loss of the Transaction Log File
Share this page                  
Recover from the Loss of the Transaction Log File
In the unlikely event of a loss of the transaction log file (or, if dual logging is enabled, loss of both file copies), the following recovery procedure can be used to restore as much database information as is possible. Follow these steps:
1. Create a new transaction log file. For more information, see the Installation Guide.
2. The next action differs, depending on whether offline or online backups take place. Included in the latter class of systems are those that employ journaling capabilities.
For offline backups
Installations using their own backup and recovery mechanisms (implying no use of online checkpoint or journaling facilities) only need to restore database directories and bring the system back up. No directed recovery is needed, after backups are done during a period when there is no system activity, and when all database information is resident on disk.
For online backups and roll forward
If you are using online checkpoints and journaled databases, bring the installation back up with the newly initialized log file. All databases open at the time of the failure can be marked inconsistent by the recovery process. Each must be recovered in turn by the roll forward database operation. The +j (Enable Journaling) option with roll forward is specified for journaled databases; this option is not specified for those databases that are not journaled.
Note:  A roll forward operation restores databases to a consistent state even if incomplete transaction histories have been copied to the journal files.