dovecot - Oct 2008 - PAM authentication problems

Hi all!
I`m using dovecot for a while with no problems.
Some days ago it started to delay the authentication until the timeout.

syslog...

Oct  3 09:00:10 coan dovecot: auth(default):
pam(rodrigo.botan,121.120.119.179): pipe() failed: Too many open files
Oct  3 09:00:11 coan dovecot: auth(default): pam(katia,121.120.200.97):
pipe() failed: Too many open files
Oct  3 09:00:11 coan dovecot: auth(default):
pam(andersoncampos,121.120.200.35): pipe() failed: Too many open files

Oct  3 08:25:55 coan dovecot: pop3-login: Disconnected: Inactivity:
method=PLAIN, rip=121.120.119.39, lip=121.120.119.251
Oct  3 08:25:58 coan dovecot: pop3-login: Disconnected: Inactivity:
method=PLAIN, rip=121.120.119.94, lip=121.120.119.251
Oct  3 08:26:01 coan dovecot: pop3-login: Disconnected: Inactivity:
method=PLAIN, rip=121.120.119.148, lip=121.120.119.251

After the commands

/etc/init.d/dovecot stop
killall -9 dovecot-auth
/etc/init.d/dovecot start

It come back to work, then after some time, I need to restart again and
again...
I tried 'ulimit -n 5000' in /etc/init.d/dovecot, but the problem
remains.

The problem is in the authentication backend, I guess.
I`m using PAM, so I leaved only one line in /etc/pam.d/dovecot:

auth    sufficient      pam_permit.so

and all worked fine. Of course, just for test, since this allows login
with any password.

My system:
Debian Etch 64bit
dovecot version: 1.0.rc15 (from etch repositories)
PAM lib version: 0.79-5 (from etch repositories)
The system has 200 users, with 30 logins per minute.
hardware: Intel(R) Xeon(R) CPU 3050  @ 2.13GHz, 2GB RAM.

If you have some pointer to the solution, it will be welcome.


Thank you,

Tom Lobato

On Oct 4, 2008, at 10:27 AM, Tom Lobato wrote:
> Oct  3 09:00:10 coan dovecot: auth(default):
> pam(rodrigo.botan,121.120.119.179): pipe() failed: Too many open files
Set this to non-zero:

# Number of auth requests to handle before destroying the process.  
This may
# be useful if PAM plugins leak memory.
#auth_worker_max_request_count = 0

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