As you may know, qmail is a mail transfer agent for Unix and Linux platforms. Nowadays, qmail has been using in many webhosting panels due to its special features like as its zero price.
The storage structure of qmail is Maildir, which means that every individual email message, has stored into a separate file. So performing the maintenance actions are easy.
In this tip, I want to show you how to find users with most used mailbox space:
1. Make an SSH session to the server (You need root account permission).
2. Find the qmail directory.
3. Use the “du” and “locate” commands together to make a mailbox usage report:
locate -b ‘\Maildir’ | xargs du -hs > /MailUsageReport.txt