[Dovecot] Out of memory after upgrading to dovecot 2.0.21

[Stan Hoeppner]

On 2/5/2013 12:15 PM, Arnaud Abélard wrote:

> I changed the vsz_limit to 512MB and it seems better, but I'm still
> surprised my mailbox actually hit the memory limit since I doubt it's
> most used one.

According to the wiki, vsz_limit only affects login processes, not IMAP
processes, which is odd given the second error you posted, which seems
to indicate a relationship between vsz_limit and imap.

>>>> dovecot: imap(abelard-a): Error: mmap() failed with file
>>>> /vmail/a/b/abelard-a/dovecot.index.cache: Cannot allocate memory
>>>>
>>>> imap(abelard-a): Fatal: pool_system_realloc(131072): Out of memory

This error suggests your mail_process_size variable is set too low.  If
it is currently set to 128MB, increase it to 512MB.  The bulk of this
memory is used for mmap()ing files, and is virtual, not physical.  Thus
you don't actually need 51GB of RAM to support 100 users.

Also, a dovecot.index.cache file of size 224MB seems rather large.  My
largest list mail folder is 150MB, contains 17,647 msgs, and has a
dovecot.index.cache file of only 16MB.  I use mbox.  This would seem to
suggest you may have a single folder with tens of thousands of msgs in
it.  Or maybe indexes are handled differently for your mailbox
format--I've not used any others.  If the former, I suggest you cull
your large folders to get them down to manageable size.

-- 
Stan