Question : Exchange 2010 hardware recommendation

I have seen this question posted a lot on these forums, and also have looked at the Dell advisory tool, Microsoft and HP's advisory tools.  I'm getting mixed responses and recommendations so I figured I would post and get some feedback on what other Exchange admins are running.

We currently have 175 users on Exchange 2007....a few have mailbox sizes exceeding 1GB but the majority are around 120MB.  They are heaving CAD/Solidworks users, and alot of them are e-mailing large attachments throughout the day up to and exceeding 8MB in size.  It hosts all the roles, does OWA/ActiveSync and is running A/V gateway software.  The users also store alot of data in local PST files and I want to consolidate everything into a single mailbox so I'd like to increase about half my users to 2GB size limits on this new hardware.

I'm currently operating on a PowerEdge 2850 Dual 3GHz Xeon w/16GB of RAM on a split backplane RAID1/RAID5.  It runs pretty poorly server side I must admit, although the end users don't notice it too much.

We are looking into migrating to Exchange 2010, and these advisor tools are telling me I need 2-4 servers and external storage while others are saying I could get by with a single beefy server with internal storage.

What's your guys recommendation?  I'm thinking my organization is small enough that I could get by on a single Dell Server with 2xQuad core processors and a RAID1/RAID 10 config with full RAID array of 15K RPM drives.  The speed of the newer sata, sas, or even SSD drives should eliminate any internal bottlenecks shouldn't it?

Answer : Exchange 2010 hardware recommendation

Single server should be fine, as long as you take precautions.   I would future-proof by getting a quality RAID controller that supports SAS-2 disks (6Gbit/sec) instead of SAS which has 3Gbit/sec throughput.   Get an enclosure with plenty of slots, so you can add additional RAID1 or RAID10 devices in future and balance the load.   Exchange 2010 is not a big CPU pig, and most of the time people are I/O bound, so I would initially get a single quad, and spend the money I save on better I/O.

I would also buy a small SSD, use it for the boot device. This will make a big difference because all of those small 4Kb I/Os that have to get done by the host O/S won't be chewing up precious IOPs that are on the exchange database devices.