During some recent house keeping on our web server, I found that a lot of hard drive space (9GB) was being eaten up by a MySQL database in the form of a file called dbg_entries.MYD within the Plesk billing MySQL database (you will only get this if you are running Plesk Business & Customer Manager in tandem with the Plesk Panel).
After a bit of research it turns out that this is caused by someone (cough, cough, Plesk support, cough, cough) leaving ‘debug logging’ enabled when its no longer needed.
Its very easy to purge the logs and to disable the logging (recommended unless you are having problems):
Go to All Settings under Business Setup
Click Debug Log under the System Information heading
Click Purge Logs to rid the system of the existing log files
Click Disable Logging to prevent any future logs building up