I'm thinking of hardware requirement for the servers going to be running. Here's the list of the servers: DC1 - it will have its own dedicated boxDC2 - virtual machineSymantec EP Manager - VMSystem Center CM 2012 - VMa smal Web Server with MS SQL -VMExchange 2010 - VM Currently I have all of them except DC1 and Exchange (I plan to install it in future) on a server with 2 x 4 core xeon processors, 24 GB ram and 4 x 1TB Sata drives in Raid 10. It handles everything, the web server is works perfectly, DC and all other stuff, but it often slow when you work with applications. Definitely I need faster speed from hard drives. But I could not decide whether to build a new server with some RAID configuration and move some of these VMs there or get iSCSI storage with many drives in it. My question is will iSCSI SAN be faster than Sata DAS, if I add more drives in RAID for SAN and use more than one Gigabit NICs? What about latency? I like the idea of iSCSI as it lets me add some other servers later, but most iportant for me is speed. any suggestions?

With everything else being equal, I don't think you would notice any difference whether you use iSCSI or DAS, assuming put storage on a dedicated NIC and network. Usually it is the disk drives themselves that are the bottleneck in any relatively small-scale storage system. What's probably more important is to increase the number of drives.Ed Crowley MVP "There are seldom good technological solutions to behavioral problems."

Thanks, I'll try building iSCSI with dedicated network and 8x 10000 rpm HDDs in Raid 50 and see what happens

What version of Exchange?Ed Crowley MVP "There are seldom good technological solutions to behavioral problems."