[imp] Performance and PHP accel question

[Tornoci Laszlo]

Hi!

I am considering a hardware upgrade to our mail system, and I want to
ask your opinion about it.

Currently we have:

HW: an IBM xSeries 232 system (1.2 GHz PIII, 3 GB RAM, 4x36GB U160 SCSI
in software RAID1 config, ext3 fs)

SW: Red Hat EL AS3, postfix, cyrus-imapd, mysql, apache, Horde3/Imp4,
amavisd-new, Spamassassin, greylisting

Usage: mostly through the web interface, only https access is allowed.
We have cca. 400 users, with 18GB mailstore usage. During peak hours we
have authentications from 40-50 different users in any 5 min interval.

The system is a lot slower than it used to be when I had set it up 4
years ago (traffic and usage went up, also Horde2->Horde3 upgrade did
make things slower). Some of the slowness is due to I/O, because
accessing the server directly through IMAPS/SMTP is sometimes slow as well.
I definitely want to separate the Horde/Imp/Apache service from the
others and move all other services to a new box (IBM xSeries 346, 3Ghz
Xeon, 2GB RAM, 6x73 GB U320 SCSI, hw RAID1).

Question #1: is separation of the services a good idea and if yes, am I
planning it the right way?

Question #2: can the current box give me fast enough service (let's say
< 5 sec waiting time) for Horde/Imp if I move all other functions to the
new box? I consider using some of the tips in Horde/docs/PERFORMANCE, a
PHP accelerator and the mcrypt module.

Question #3: which _free_ PHP accelerator do you recommend, what is your
experience with them?

                                 Yours: Laszlo