Hardware requirement

You haven't exactly provided a lot of information here.  If each person is receiving 10 small e-mails a day that's very different from each one receiving 100 e-mails a day with 5 MB attachments on most.

And since you're going with Exchange 2003, unless you go with the enterprsie version, you'll be stuck having to limit your users with about 250-300 MB quotas on their mailboxes (information store on Exchange 2003 standard is maxed out at 75 GB).

With SQL, if the system is NOT used an e-commerce app, then most servers should be fine... the difference will come in how well (or poorly) your database is designed and SQL is tuned.

Personally, from what I can imagine (and this is NOT a good way to gauge - imagining) I would probably go with a standard SINGLE Dual core system with 4 GB of RAM for Exchange.  Make sure the hardware can expand to two processors and ideally support quad core, but to start, there should be no reason you NEED two physical processors or a quad core (I've worked in organizations supporting 1000 users on machines FAR LESS powerful than anything available new today and they have no problem supporting hundreds of users (from a processor perspective).  I would suggest the disks for both servers look like this:

8 total SAS disks:
2x36 GB for the OS in a RAID 1 (bump to 73 GB if 36 aren't available)
2x73 GB for the Database Logs in a RAID 1
4x300 GB (or larger or more drives in an even number) for the Database Data drives in a RAID 10, depending on how much data you may need to store.

The SQL server I would probably start out the same way... though MAYBE I'd consider a single Quad Core CPU.  If you buy SQL licensed by the processor, this will be a very cost effective way to run it - MS licenses according to SOCKETED processors, NOT Cores.

Thanks leew

Experts any more suggestions?

I would tend to agree with leew with the following exception, buy quad core processors.  The reality is there is not a very large price ga between dual and quad, so you might as well spend the exta couple of $ and get the quad.

DEFINATELY DEFINATELY DEFINTELY buy SAS disks, it may look a little more attractive price wise, but SATA disks will slow you down.

What are SAS disks?

SAS stands for Serial Attached SCSI.  A good definition can be found here:

http://webopedia.com/TERM/S/SAS.html

Most quad cores don't operate at the high MHz that dual core chips can.  A faster dual core can make more sense than a slower quad core.  In addition, I want to stress, you SHOULD get a system capable of supporting Quad Cores and you can always upgrade to them later with minimal downtime.

Hi,

there is tool call exchange loadsimulator which will give you some idea about server sizing.

but this toll need tobe run on test enviroment as it will create dummy users as per your requirement.

Rgds

>Data files are best placed on a RAID-5 array because they have faster read speed thanother RAID arrays

Where did you get that one from? RAID 10 read speed is the same as RAID 5 read speed as long as there are the same number of disks and the controller does balanced reads.

Thanx

Thanx