[SOLVED] DBCC SHRINKFILE on log file not reducing size even after BACKUP LOG TO DISK

DBCC SHRINKFILE on log file not reducing size even after BACKUP LOG TO DISK

I've got a database, [My DB], that has the following info:
SQL Server 2008
MDF size: 30 GB
LDF size: 67 GB

I wanted to shrink the log file as much as possible and so I started my quest to figure out how to do this. Caveat: I am not a DBA (or even approaching a DBA) and have been progressing by feel through this quest.

First, I just went into SSMS, DB properties, Files, and edited the Initial Size (MB) value to 10. That reduced the log file to 62 GB (not exactly the 10 MB that I entered). So, I attached SQL Profiler, saw that DBCC SHRINKFILE was being called. I then entered that command into the query editor and here's the results.

DBCC SHRINKFILE (N'My DB_Log' , 10)

And the output was:

Cannot shrink log file 2 (My DB_Log) because the logical log file located at the end of the file is in use.
DbId   FileId      CurrentSize MinimumSize UsedPages   EstimatedPages
------ ----------- ----------- ----------- ----------- --------------
8      2           8044104     12800       8044104     12800

(1 row(s) affected)

DBCC execution completed. If DBCC printed error messages, contact your system administrator.

I then did some research on that and found this:

http://support.microsoft.com/kb/907511

Which says that I need to backup the log file before the shrinkfile so that the virtual log files will be released and the shrinkfile can do its job - I don't know what that means... I'm just paraphrasing here :)

So, I figured I'd try to backup the log file and then do a DBCC SHRINKFILE (and I changed the new log file size to 12800 since that was the MinimumSize identified in the output of the previous DBCC SHRINKFILE command)

BACKUP LOG [My DB] TO DISK = 'D:\SQLBackup\20110824-MyDB-Log.bak'
GO
DBCC SHRINKFILE (N'My DB_Log' , 12800)
GO

The result was the same as the first go around. I can only get the log file down to 62 GB.

I'm not sure what I'm doing wrong and what I should try next.

Solution

In addition to the steps you have already taken, you will need to set the recovery mode to simple before you can shrink the log.

THIS IS NOT A RECOMMENDED PRACTICE for production systems... You will lose your ability to recover to a point in time from previous backups/log files.

See example B on this DBCC SHRINKFILE (Transact-SQL) msdn page for an example, and explanation.