  No - the avoidance of SATA disks and use of only SAS <500Gb was mainly down to best practices research, but as mentioned above, cost always come in to it when choosing disks. I did say in my first post to ignore financials, as I wanted to get a conversation based purely on disk performance, without the inclusion of $ per MB. I recently spoke to a NetApp Partner who said he would never sell disks >500GB for virtualisation, but with the latest advancement in HDD and their onboard cache, I was wondering whether what was best practice a year ago is no longer best practice and that it need re-evaluating; i.e. 1TB are now safe to use for high work loads.     NetApp and Equallogic customer here.  1 year ago, the NetApp Partner was dealing with a technical limitation -- the amount of drives one could pool into a NetApp unit of performance ("aggregate") had to be under 16TB, at one point this was including RAID parity drives. So the most perofrmance he could sell with 1TB was at that time the equivalent of 13 1TB data disks (parity doesn't contribute to app performance).  Horrible. The issue of buying large drives is more like a problem of organizational disclipline:  Can you deal with the staggering amount of space efficiently even if you run out of iops (trapped capacity)?  It's that tendency to keep packing twice as much data as a 500GB drive that leads to problems, and given the above, nothing to do with the drives themselves.
Hi, I am looking at getting an Equallogic for virtualisation. I have run capacity planning tools, and my IOPS requirements are quite small, so I would be able to make use of Nearline SAS in a 24xHDD PS6100E. However, I am stuck as to whether 1TB disks are too large to use for virtualisation, because of their seek times? I did read over a year ago, that you should never use disks larger than 500GB for virtualisation, but is this still the case? Finance and disk space issues are exempt here, and the priority requirement here is to ensure performance.
Design Disk Sizes for Virtualisation