[dovecot] Re: Failure in the presence of too many connections

Mark E. Mallett mem at mv.mv.com
Mon Mar 31 22:27:13 EEST 2003


On Mon, Mar 31, 2003 at 02:19:27PM -0500, Charlie Brady wrote:
> 
> On Mon, 31 Mar 2003, Mark E. Mallett wrote:
> 
> > The only way to make the services start responding again is to stop and
> > restart the dovecot suite of control processes. dovecot suite of control
> > processes.
> 
> Or you can run things my way (under tcpserver/stunnel/imapfront-auth) and 
> there's one dovecot process for each connection, each unrelated. This 
> illustrates my point about re-using already well trusted simple programs
> to do as much of the task as possible. 

yep- this kind of brings us full circle back to my original message :-)
(I had mentioned that this kind of problem may be less likely with
a tcpserver approach).

Although the distinction is not between using well-trusted simple
programs vs large monolitic ones, but how you access those simple
programs.  Do you use a long-running auth process and talk to it via a
UNIX socket (or other inteface), or fire up a new auth process for
each need?  Personally I'm with you: unless there's an awful lot of
state or caching or other long-term need that you lose by creating a
new auth process each time (e.g.  like innd's "actived" process), I'd
vote for a one-time short-running auth process.


> > Raising the openfiles limit
> > certainly pushes off the problem, and maybe that's a good enough
> > workaround (as long as there's always a higher limit availble...)
> 
> ... which is something that you can *never* assume.

Amen

mm



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