From: Yu (Irvin) Fan ("Yu)
Date: Thu Feb 12 2009 - 20:47:55 EST
We're building a box to run two postfix instances to receive and send high
volume of emails. According to the documentation it's better to run the two
instances on separate disks for performance reason. I'm trying to understand
how exactly does the disk I/O affect the postfix performance? By speed
(bytes per second) or activities (# of read/write per second)?
Let's say I have two hard disks. If I make a RAID0 array out of the two
disks the overall speed is twice as the speed of a single drive (I know it's
not exact twice the speed. just simplify it for discussion). If the postfix
performance depends on the disk speed then running two instances on two
separate disks or running two instances on one RAID0 array should not make
big difference, right? But if it depends on disk activities then running on
two separate disks is definitely better. I know no matter which case using
two disks is the choice. But if I have other reason to use RAID0 I just want
to know how much performance I lost in postfix?