[CentOS] How to size an email server to handle 5 million emailsperday

> Right, actually the box will run an AV engine with antispam then
> delivered to a ms exchange 2003 server (local lan), so no local
> mailbox is being used.

oh okay. Do you plan to build the system? (the software involved)

You needs will vary on how emails are dwelt with at the smtp level. How 
did you come by the 5 million figure? If you are really going to scan 
that many, you will need lots of cpu power besides really good disk i/o 
if you plan to use a single box to handle everything.

> 
> The barracuda spam firewall 400 appliance handles my specs but i
> cannot get info on what hardware they run, it's a 1u raid1, linux
> hardened presentation but no idea of the cpu or ram.

They most probably make heavy use of NVRAM or whatever they use for the 
memory cache of the RAID system. The service provider was once providing 
with two boxes from F5 for testing and its i/o was fantastic and they 
somehow used the RAID cache to do their guarantee of not losing any 
email under any circumstances.

> 
> And no, it won't be used for marketing, it's inbound only.

If you do get a barracuda, please be sure to bin crap that you do not 
reject at the smtp level. Otherwise, you will be marked as an outscatter 
'spammer'.