[Dovecot] Dovecot 1.0-rc15 on Solaris 10

[Steven F Siirila]

On Tue, Jan 02, 2007 at 11:23:10AM -0600, Steven F Siirila wrote:
> We are running Dovecot 1.0-rc15 on Solaris 10 and are starting to ramp up
> our user count and ran into a file descriptor limit:
> 
> Jan  1 19:38:54 <hostname> dovecot: IMAP(username): Newly created index file is corrupted: /home/username/.imap/foldername/dovecot.index.tmp
> Jan  1 19:38:54 <hostname> dovecot: IMAP(username): file mail-index.c: line 1806 (mail_index_move_to_memory): assertion failed: (index->fd == -1)
> Jan  1 19:38:54 <hostname> dovecot: pipe() failed: Too many open files
> Jan  1 19:38:54 <hostname> dovecot: Temporary failure in creating login processes, slowing down for now
> 
> We got around this by calling "ulimit -n 512" and restarting Dovecot.

We have since set this limit to "unlimited".

> This got us further (upwards of 300 concurrent users), but we are now
> running into what appears to be a full listen queue (connections are
> not rejected, but rather slow in being established).

This turned out to be a result of using the default value for
login_max_processes_count (128).  We now have this set to 4096
in anticipation of our moving thousands more users to the server.
We've also bumped login_processes_count from 3 to 32.

> What I would like to know is if anyone else out there runs with large numbers
> of concurrent IMAP sessions via Dovecot and has run into problems.
> If so, did you have to up your fd limit w/ulimit?  Any other issues?

Is anyone else out there running with thousands of concurrent sessions?
On our older (existing) UW IMAP servers we have seen upwards of 3000
concurrent sessions.

-- 

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