Changing the recovery mode doesn’t shrink an SQL Database log file, how to shrink logs manually.


So I found out recently that one of our servers was running out of space.  It’s our AV server so I was like what the hell, why is it running out.  Turns out it had an instance of SQL Server on there as a quarantine and configuration database.  The Virtual Machine was being backed up but not the database itself therefore no log back ups and log truncates after that.

To check exactly how much space the logs are taking up you can run the following SQL cmd:

SELECT * FROM <database>.sys.sysfiles

Or you could just as easily right-click the database and check file sizes from there.

To fix this I simply changed the recovery mode from FULL to Simple for the databases, but without a backup of the databases themselves the logs wouldn’t truncate.  Doing a backup from the right-click menu won’t truncate them either.  Since I wasn’t really worried about backing up the database itself I could just force SQL Server to truncate the logs.  I ran the following command to shrink the log file:

DBCC SHRINKFILE('<database_log>')

With <database_log> being the name of the database log file you want to shrink.  That solves that problem.


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