Friday, December 14, 2007

Exchange 2003 running out of transaction logs

This issue cropped up for me in one of our sites in Europe this week so I thought this might be worth posting. Exchange transaction log files are automatically created once the storage group and database is mounted. As the current log file E00.log reaches its limit (5MB for pre-Exchange 2007 and 1MB for Exchange 2007) the file is renamed with a sequential hexadecimal number that allows the log files to be replayed in the correct order.

For example when the First Storage group current log file E00.log reaches the limit it is renamed to E0000001.log and then the second to E0000002.log, etc. This sequence can go as high as E00FFFFF.log. Exchange can generate 1,030,000 unique log files. Once this limit is reached the databases of the affected store will dismount and won’t be able to remount until the log file sequence is reset. It can take years in most Exchange deployments to reach this limit however the heavier the load on the storage group the quicker this will occur.

The Exchange Analyzer Tool will report if your system is running low on available transaction logs. If you need to reset the log file sequence make sure that you have a full backup of the affected databases and that the databases are in a clean shutdown state.

Further Information
Transaction log file names running out

1 comment:

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