We recently upgraded our Cyrus IMAP server from 1.5.14 (really old version),
to 2.0.16. Since that time, it appears that we keep hitting against process
limit issues. It is unclear exactly how many processes it takes to hit this
limit, however, it seems to be considerably less than what the system thinks
it should be.
The kern.log file shows the following line:
vmunix: task_create() failed for pid 207736: max_proc_per_user
(=3036) exceeded for uid 110.
The imap log shows failed forks and so forth, as you would expect. The
difference between the old imap server is that the old server ran from
inetd and the new server runs as a standalone server that spawns off all
the imap children. The inetd daemon is running as root, and when the
imap process is spawned, it changes itself to the cyrus user (uid=110).
With the new server, which is called "master", it starts as root, but
changes to the cyrus user right away. From that point on, all the imap
processes spawned are already owned by the cyrus user. I am not sure
if this is part of the problem or not.
In any the case, we easily had a couple thousand imap processes running
before we upgraded, and now we are lucky to get much above 1000 processes
with the new server. The sysconfigtab shows the following for the "proc"
section on our machine:
maxusers = 2048
max_proc_per_user = 3036
max_threads_per_user = 4096
By the way, the new version of the imap server is linked with BerkDB 3.2,
which of course uses pthreads, so there are threads involved... But since
we use flat-file format for our mailboxes database and only use db3 for
our duplicate delivery supression database, I don't think we are seeing
lots of threads running around. The error message does suggest a maxproc
thing and not a maxthread thing.
Finally, our system is Tru64 5.1 with Patch Kit 3.
Thanks,
Scott
--
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Scott W. Adkins http://www.cns.ohiou.edu/~sadkins/
UNIX Systems Engineer mailto:adkinss_at_ohio.edu
ICQ 7626282 Work (740)593-9478 Fax (740)593-1944
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CNS, HDL Center, Suite 301, Ohio University, Athens, OH 45701-2979
Received on Mon Sep 10 2001 - 21:16:13 NZST