Subscription backup finished with warning “The transaction log for database ‘X’ is full” on Plesk server

Symptoms

• Subscription backup finished with warning:

  Warning: Unable to back up database content. ["The transaction log for database 'X' is full."]

•  It is not possible to set maximum log file size for database in Plesk UI. The following error is shown:

  Error: Unable to set the maximum log file size of the database: 'mssqlmng failed: The transaction log for database 'example_db' is full due to 'LOG_BACKUP'. 

• Unable to change a database user login or password at Domains > example.com > Databases > User management > johndoe:

  Error: Delete database user failed: mssqlmng failed: The transaction log for database 'example_db' is full due to 'LOG_BACKUP'.

• Unable to export a database dump at Domans > example.com > Databases > <db_name> Export Dump:

  Unable to export a dump of example_db:
  Unable to backup database 'example_db' 
  The transaction log for database 'example_db' is full due to 'LOG_BACKUP'. 
  BACKUP DATABASE is terminating abnormally. 
  (Error code 21) 

Cause

The transaction log has reached its configured size or disk does not have sufficient space.

Resolution

Back up the Transaction log following the below steps:

1. Connect to the server via RDP;

   Note: If direct RDP access to the server is not possible, contact server administrator for further assistance.

2. Go to MSSQL Server Management Studio > <server_name> > Databases > right-click example_db > Tasks > Back Up...

3. On the General page, select Backup type: Transaction Log.
4. On the Media Options page, selected Truncate the transaction log and click OK.
   

Additional information

Troubleshoot a Full Transaction Log (SQL Server Erro 9002).