[Dovecot] No buffer space available

[Rick Romero]

Hi,

I'm running Dovecot 1.1.3 on FreeBSD 7.0.    In the past couple days, 
I've been seeing errors like this:

Sep  9 08:43:51 sysvol dovecot: pop3-login: socketpair() failed: No 
buffer space available
Sep  9 08:43:51 sysvol dovecot: pop3-login: socket(default) failed: No 
buffer space available
Sep  9 08:43:51 sysvol dovecot: pop3-login: Can't connect to auth server 
at default: No buffer space available
Sep  9 08:25:15 sysvol dovecot: pop3-login: socketpair() failed: No 
buffer space available
 pop3-login: Can't connect to auth server at default: No buffer space 
available

What ends up happening is that the port doesn't accept any new 
connections until there is enough buffer space.

Yesterday, I saw it a LOT with POP3 and changed my config login processes:
login_process_per_connection: no
login_process_size: 256
login_processes_count: 6
This seemed to clear up the issues, but now it's occurring again this 
morning.

I haven't had any of these since I made that change either.. So there's 
some progress... :
Sep  8 12:53:40 sysvol dovecot: Temporary failure in creating login 
processes, slowing down for now


TOP shows:
Mem: 267M Active, 5558M Inact, 1637M Wired, 217M Cache, 214M Buf, 87M Free
Swap: 4096M Total, 4096M Free

At this time, there are 120 imap processes, 10 POP and 1 dovecot and 1 
dovecot-auth
pop and imap both have 6 login processes.  
It doesn't seem like a load issue, but obviously something is set too 
low or unavailable... 

It's fixed for a period of time when I restart dovecot.  I did a netstat 
-m prior to restart, and after restart, and the only main difference was 
this line:
Before:
11/414/425/12800 4k (page size) jumbo clusters in use 
(current/cache/total/max)
After:
0/425/425/12800 4k (page size) jumbo clusters in use 
(current/cache/total/max)
(After about 5 minutes 'current' went to 3)

This machine also runs NFSd and MySQL.  

Any ideas?

Thanks,
Rick