Why is my msdb so large?

msdb is a system database used mainly by the SQL Server Agent to store system activities like SQL Server jobs, mail, service broker, maintenance plans, user and system database backup history, etc.

Like any database it needs to be monitored and maintained. You may find that your msdb database has grown significantly.

What may have caused this could be:

- retention of backup history

- maintenance plan logs

- database mail

- job history

To reclaim control over the space in msdb you need to look at deleting data out of the large tables. By looking at the table sizes you can determine what is causing your issues. Most of the time it is just a matter of running a stored procedure to do this cleanup.

For example:

a) sp_delete_backuphistory

b) sp_maintplan_delete_log

c) sysmail_delete_mailitems_sp

d) sp_purge_jobhistory

Then you could shrink the msdb data and log file to reclaim disk space.