Hi,
The main issues to consider when sizing a mail system are:
- quota per user, and percentage full the "average" user will have their
mailbox, the way they access their mail for reading also matters. You can
get away with significantly less storage for a POP implementation versus an
IMAP setup.
- I/O, there are many things to consider here:
- redundancy, you need to allow for drive failure, adapter card
failure, cable failure, disk box failure.
- performance, NEVER use RAID 5 for your mailstore. I don't care
if it is a hardware RAID box
or not, just don't do it. It will not scale well. Write cache
is a wonderful thing. I prefer striping
and mirroring for a mailstore, aka RAID 0+1 and/or RAID 1+0
depending on the volume mgr.
- contention, split your I/O load over multiple paths if possible.
- CPU, just needs to be enough to drive the I/O load.
- Memory, really important on an IMAP implementation, POP just needs enough
to handle your largest expected simultaneous load.
Jim
> >
> > The setup (2 stock PCs with 2GB RAM and 2xCPU at 1.xGHz with Linux-2.4.x
> > and ReiserFS) did not glitch very much, load never went beyond 4 I think
> > and - thats more important - connect/select/fetch times of all clients
> > almost never did exceed 1 second.
With a load of 4, what was your bottleneck?
>Thanks, this is a useful data point.
>
> -Guy
