Postfix Question

On my server plans I have the maximum size as 2Gb, and mail boxes can be "unlimited" i.e. can grow to the maximum of 2Gb. (Or so I hope).

However in webmin >> servers >> postfix >> resource settings, the "max size of a mailbox" says just 50Mb.

This could cause problems, couldn't it? (Now I've noticed that, I have set the Postfix value to 2Gb, but it would be nice if Virtualmin took care of that automatically)



That setting shouldn't actually cause any problems, as it only applies to mbox-format mailboxes which use a single file .. and a default Virtualmin install use Maildir format.

However, you should change the "max size of mailbox" to "unlimited", as it can prevent postfix and procmail from writing to log files larger than 50 MB in some cases.

This setting "mailbox_size_limit" in Postfix has certainly got me puzzled!

Like I guess many admins, I wanted to increase the maximum message size beyond the 10Mb default. So I did that and did not notice that I set it to higher than the maibox size limit (which is illogical after all). The result? Postfix stopped delivering emails and the queue started growing. By the time I caught on, the queue was 2500. In the logs I had this:

"fatal: configuration error: mailbox_size_limit is smaller than message_size_limit"

So I reduced the message size to 35mb - and immediately crashed the server (a 2000Mhz 3Gb RAM instance at I eventually figured out the problem - I had caused a "Postfix bomb" as I had not altered the "default_process_limit" from 50. (IMO that is far too high a default for most servers to cope with!). When I changed it to 3 the queue subsided (and I later upped it to 8).

Once my nerves had settled, I tried again. All I needed to do to was set 100Mb for "message_size_limit" and 2Gb for "mailbox_size_limit". But no...Again Postfix died with "fatal: configuration error: mailbox_size_limit is smaller than message_size_limit". How can that be?

Well when I did postconf –d | grep size, although the mailbox_size_limit was 2Gb in Webmin, according to Postfix it was still 50Mb.

Next I followed your advice and set "unlimited" (i.e. "0") for mailbox_size_limit. The good news? Postfix works with that. But the puzzling thing (to me) is that with postconf -d I STILL see a value of 50Mb for mailbox_size_limit.

Well, for me at least, the problem is solved. But I wonder if it wouldn't be a bad idea to get Webmin and Postfix to be consistent about this value (if possible)? And my other suggestion would be to make, say, 10, or even 5, the default value for "default_process_limit".

I'm actually surprised that mailbox_size_limit was set at all on your system, as the Virtualmin installer sets it to 0, which means unlimited..