mupdate cpu, thread timeouts

[John Madden]

Lately, I've been seeing a lot of this from imap frontends, repeating 
over and over:

Jul  1 15:15:52 imap mupdate[18206]: unready for connections
Jul  1 15:15:52 imap mupdate[18206]: synchronizing mailbox list with 
master mupdate server
Jul  1 15:16:51 imap mupdate[18204]: Thread timed out waiting for 
listener_lock
Jul  1 15:16:51 imap mupdate[18204]: Worker thread finished, for a total 
of 4 (3 spare)
Jul  1 15:16:51 imap mupdate[18204]: Thread timed out waiting for 
listener_lock
Jul  1 15:16:51 imap mupdate[18204]: Worker thread finished, for a total 
of 3 (3 spare)
Jul  1 15:16:51 imap mupdate[18204]: Thread timed out waiting for 
listener_lock
Jul  1 15:16:51 imap mupdate[18204]: Worker thread finished, for a total 
of 2 (2 spare)
Jul  1 15:16:51 imap mupdate[18206]: mailbox list synchronization complete
Jul  1 15:16:52 imap mupdate[18206]: New worker thread started, for a 
total of 1
Jul  1 15:16:52 imap mupdate[18206]: New worker thread started, for a 
total of 2
Jul  1 15:16:52 imap mupdate[18206]: New worker thread started, for a 
total of 3
Jul  1 15:16:52 imap mupdate[18206]: New worker thread started, for a 
total of 4
Jul  1 15:16:52 imap mupdate[18206]: New worker thread started, for a 
total of 5
Jul  1 15:16:54 imap mupdate[18203]: unready for connections
Jul  1 15:16:54 imap mupdate[18203]: synchronizing mailbox list with 
master mupdate server
...

mupdate, during these times, consumes an entire core for quite a bit of 
time.  There are a lot of matching thread timeout errors on the master, 
also consuming cpu.  Also during this time, mailbox changes (CREATE/etc) 
are delayed or timeout.

This is a 2.3.15+murder system with about 2.8mil mailboxes, two 
frontends, 6 backends, and a single master.  Any suggestions?

John





-- 
John Madden
Sr UNIX Systems Engineer
Ivy Tech Community College of Indiana
jmadden at ivytech.edu