The log files were an obvious first stop. I still had a ton of space i needed to find where it was being used. My file system showed only a couple gigs and my database was only a couple more, yet I was approaching on 20GB of used space. Where was the rest of it?

Turns out, it was all spam and bounces from registration emails, etc from my forums.

cPanel sets up the default catch-all to go to the accountname@domain.com. ie, if you named your site mysite01, cPanel defaults itself to forward all un- pop3′ed addresses to this account.

IMAP is the only way to get into it (easily), so i opened up Horde and nearly spit my beverage on my monitor. One account had 145,000 odd emails in there, and 4 others had over 50,000 emails in there. My not so popular domains still had a couple thousand in them from just years of collecting viagra and stock quote spams.

I easily recovered 10% of my /home volume just by deleting spam and bounce emails.

The easy way to fix this is to go into WHM’s Tweak Settings at the top, and change the default on New Accounts to :fail: instead of :blackhole:. Unfortunately, this is NOT retro-active, so you will need to go into each of your accounts sub-cpanels and change the catch-all in there from :blackhole: (or “forward to” if you have the new cPanel template) and set it to :fail: (if you have the new template, select the radio button that says “discard with error at SMTP…”).

Lesson Learned. the Blackhole is a bad thing, and the default forwarder is even worse.

10% is a lot of space, especially when you consider most emails are in the 2-3Kb range.

So, if you’re running out of space, and you’re a novice dedicated server admin like myself, check your mail settings. You might be surprised too.