SUMMARY
Information if backups are scheduled and running on the database but the logs are growing and eventually fill up the disk space.
ISSUE
Purpose
Keep the SQL Server logs from consuming all the server disk space.
Applies To
Microsoft SQL Server 2005 through Microsoft SQL Server 2014
Symptoms / Description
Backups are scheduled and running on the database but the logs are growing and eventually fill up the disk space.
Cause
Unitrends backup agent does not control the size of the log file on disk. The Unitrends agent after a successful transaction log backup will signal to SQL Server that the backup has been completed and the log can be truncated. There are several factors that can delay SQL Server's ability to truncate the logs so it is very important to monitor the size of the log file. Truncating the log file DOES NOT change the size of the log. If the size of the log has grown then a shrink operation will need to be performed to reduce the log size on disk.
Resolution / Workaround / Execution Process
To get the database log size back under control a shrink operation should be run on the database and another Transaction Log backup will need to be performed.
One way to keep the log files from growing too much is to run more frequent Transaction Log backups. With more frequent Transaction Log backups the log is being truncated more frequently and the log doesn’t have time to grow and fill up the disk.
A second option is to run a shrink operation via a maintenance plan before a full backup is scheduled to run.
Third-Party Sources
https://docs.microsoft.com/en-us/sql/relational-databases/logs/the-transaction-log-sql-server