We want to set up a low-budget environment to support multiple concurrent test environments for our small business. Our application suite (the basis for each VM) is a stack consisting of a web-based ASP.Net application with SQL Server 2005 database, coupled to a back-end VB.Net Windows console application coupled to its own separate SQL Server 2005 database. Each VM would be single user only for testing purposes, and would be about 75Gb in size. We'd probably have 5-6 VM's up and running at any point in time.
We're looking to re-purpose an old HP server as a SAN, upgrading it with 4 Tb SATA disks and using FreeNAS or OpenFiler (the server only has physical capacity for 4 disks). What RAID configuration would be best for us?
Depends on what sort of fault tolerance you need,
If you simply want saomething uick and don't care for data loss, just stripe them.
If you want a balance of speed and fault tolerance - Raid 5.
Looking at what you want though - 6vms x 75GB is only 450GB - so you have LOADS of space.
Best performance and FT would be Raid 1 + 0 (though this will of course use the most disk space) (Also known as Raid 10 or Raid 01)
you need to know the total IOPS your virtual machines would need, and from there you can decide to use a SATA/SATA disk and the number of them to cater the total disk IOPS. then you need to make sure that raid penalty is take into consideration.
Lefthand VSA is a good start and we have deployed it for many small setup.