On Thu, 2010-12-09 at 10:18 -0800, Mark Moseley wrote: > Upping the client_limit actually results in less processes, since a > single process can service up to #client_limit connections. When I > bumped up the client_limit for imap, my context switches plummeted. > Though as Timo pointed out on another thread the other day when I was > asking about this, when that proc blocks on I/O, it's blocking all the > connections that the process is servicing.
Yeah. And it's even worse if it's blocking on waiting for a lock. BTW. Do you have these kind of error messages in your log: net_connect_unix(pop3) failed: Resource temporarily unavailable net_connect_unix(imap) failed: Resource temporarily unavailable I think those are sometimes happening when not using client_limit=1, because all the processes are busy at that time and can't accept a new connection (while with client_limit=1 a new process would be created to handle it).
