MySQL quota exceed

[CyberCr33p]

When user filesystem quota exceed, and mysql tries to write on a database, mysql locks EVERY table/database and waits for some free disk to finish the write.

So every website that uses php/mysql is down until the user deletes some files.

How cpanel handles this issue?

[cpanelkenneth]

Don't apply user quotas to MySQL at the file system level. MySQL was not designed for file system quotas. It should work adequately for group quotas.