We have a new storage array consisting of 24 x 600GB 10K SAS disks arriving next week, and I'm trying to decide how best to carve up the available space for our 3-node VMware vSphere cluster which will be accessing the array over 8Gb FC with fully redundant multipathing.
We have two main workloads - in-house MySQL and Exchange 2010 servers which I'll class as high-IO and Windows domain controllers and a fileserver, which I'll class low-IO.
My initial plan was to split the array with 6 disks in RAID10, with the other 18 in RAID50, using either three 6-disk RAID5 silos, or six 3-disk silos. The enclosure doesn't have a "hot spare", but we've ordered an extra disk as an on-site "cold spare".
Now, this works in principle, but I'm unsure how safe it will be in practice - I've read several articles and although the increased space efficiency is swaying me in the direction of RAID50, several posts I've seen essentially say that RAID50 (along with RAID5) has been deprecated in industry due to unreliability and failure risk.
Am I being paranoid unnecessarily, and if not, should I use RAID10 silos instead of RAID50?