[imp] system / imp tuning

[Colin Devine]

Hello,

We recently upgraded our Horde/Imp install from horde 1.2.6/imp 2.2.7 to
2.1/3.1.  Also included in this was an upgrade to php-4.1.2.  Since then
we notice that our apache processes grow in the amount of memory they
use as time progresses, slowing down the server and IMP itself.  At the
start of the apache server they are ~7M but in about 24 hours they are
often ~25M in size.  This seems to me to indicate a memory leak of some
sort and I was wondering what the collective knowledge base of this list
had any ideas.  

I include my ideas as starting points.

1) Restart the server every x hours, where x is at least 24.  We did
this previously with the old horde/imp and perhaps this was helping us
more than we realized.

2) Change MaxRequestsPerChild to maybe 5000-10000 instead of 0 (0 being
the child processes never die).

We are also investigating php accelerators, imap proxies, and even
multiple clustered webmail servers in an effort to load balance and
generally speed up IMP.

All thoughts comments and questions are encouraged.

Thanks and have a nice day.

--Colin Devine