[Dovecot] too many open files and v1.2
Hi
I've found an older thread http://www.dovecot.org/list/dovecot/2010-March/047886.html which mentions that this is a bug in version 1. I'm on Debian squeeze (1:1.2.15-7) and got errors like these recently
Oct 5 11:29:29 mail dovecot: dovecot: pipe() failed: Too many open files Oct 5 11:29:32 mail dovecot: dovecot: pipe() failed: Too many open files Oct 5 11:29:32 mail dovecot: dovecot: Temporary failure in creating login processes, slowing down for now
As a work around I've increased login_max_processes_count from 256 to 512 and it seems to have helped (as I suspected stale opened files).
My colleague thinks it's hitting the kernel open file limit ulimit -n (currently at 1024) but I don't see how that could happen if the number of process is nowhere near that.
Any ideas?
Thanks,
Michael
On Thu, 2011-10-06 at 12:42 +0100, Michael Moritz wrote:
Hi
I've found an older thread http://www.dovecot.org/list/dovecot/2010-March/047886.html which mentions that this is a bug in version 1. I'm on Debian squeeze (1:1.2.15-7) and got errors like these recently
Oct 5 11:29:29 mail dovecot: dovecot: pipe() failed: Too many open files Oct 5 11:29:32 mail dovecot: dovecot: pipe() failed: Too many open files Oct 5 11:29:32 mail dovecot: dovecot: Temporary failure in creating login processes, slowing down for now
These errors come from the dovecot master process. Each child process uses up a few fds for pipes.
As a work around I've increased login_max_processes_count from 256 to 512 and it seems to have helped (as I suspected stale opened files).
That only makes it easier to reach, since now there can be more child processes eating up more fds.
My colleague thinks it's hitting the kernel open file limit ulimit -n (currently at 1024) but I don't see how that could happen if the number of process is nowhere near that.
I don't remember how many fds each process takes in v1.x, probably between 1 and 3. So if you for a while had hundreds of imap or pop3 processes, you could run into that limit.
v2.x doesn't use as many fds.
Hi Timo
thanks for your reply. I understand you're basically saying "upgrade to v2" but maybe this could be of interest for you. After we lowered the login_max_processes_count again the problem reappeared so I'm not sure whether that doesn't indicate a different problem.
Regards,
Michael
On Tuesday 18 October 2011 15:57:23 Timo Sirainen wrote:
On Thu, 2011-10-06 at 12:42 +0100, Michael Moritz wrote:
Hi
I've found an older thread http://www.dovecot.org/list/dovecot/2010-March/047886.html which mentions that this is a bug in version 1. I'm on Debian squeeze (1:1.2.15-7) and got errors like these recently
Oct 5 11:29:29 mail dovecot: dovecot: pipe() failed: Too many open files Oct 5 11:29:32 mail dovecot: dovecot: pipe() failed: Too many open files Oct 5 11:29:32 mail dovecot: dovecot: Temporary failure in creating login processes, slowing down for now
These errors come from the dovecot master process. Each child process uses up a few fds for pipes.
As a work around I've increased login_max_processes_count from 256 to 512 and it seems to have helped (as I suspected stale opened files).
That only makes it easier to reach, since now there can be more child processes eating up more fds.
My colleague thinks it's hitting the kernel open file limit ulimit -n (currently at 1024) but I don't see how that could happen if the number of process is nowhere near that.
I don't remember how many fds each process takes in v1.x, probably between 1 and 3. So if you for a while had hundreds of imap or pop3 processes, you could run into that limit.
v2.x doesn't use as many fds.
participants (2)
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Michael Moritz
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Timo Sirainen