[Dovecot] memory allocation issues

[Kelsey Cummings]

One of our dovecot backend servers ran into a problem with it's auth
process a few days ago.  This doesn't appear to be the error logged when
dovecot hits its internal limit so I'm not sure what is going on here.

auth: Error: malloc: 58012: Cannot allocate memory
auth: Error: Unable to allocate memory for mutexes from the region
auth: Error: PANIC: Cannot allocate memory
auth: passwd(test,1.1.1.1,<8HTlNHzNIQBAjhKC>): unknown user
pop3: Error: Authenticated user not found from userdb, auth lookup +id=2509111297 (client-pid=4781 client-id=1)
pop3-login: Internal login failure (pid=4781 id=1) (internal failure, 1 +succesful auths): user=<test>...

There was at least 10+GB free RAM on the server and no indication of a
system level issue at the same time.  The server is running 2.1.9.
There were about 3,200 active sessions, with something like 12 new
sessions/sec.  The other identical servers are/were handling virtually
identical load with the same service uptime and haven't had any issues 
so far.  (Crash happened 7 days ago.)


-- 
Kelsey Cummings - kgc at corp.sonic.net      sonic.net, inc.
System Architect                          2260 Apollo Way
707.522.1000                              Santa Rosa, CA 95407