Further to my earlier post on XenServer storage performance with regards to directly attaching storage from the host, I have been analysing the performance of various SSD storage options.
I have attached a HP DS2220sb storage blade to an existing server blade and compared performance with 4 and 6 SSD RAID-10 to our existing iSCSI SANs.
While the P420i RAID controller in the DS2220sb is clearly saturated and unable to provide throughput much over 1,100MB/s - the IOP/s available to PostgreSQL are still a very considerably performance improvement over our P4530 SAN - in fact, 6 SSD’s result in a 39.9x performance increase!

Sam McLeod

A performance comparison of direct-attach SSD storage using an HP DS2220sb storage blade versus iSCSI SANs in a XenServer environment. Testing 4 and 6 SSD RAID-10 configurations reveals that while the P420i RAID controller saturates around 1,100MB/s throughput, PostgreSQL IOPS still show a dramatic improvement — up to 39.9x over the existing P4530 SAN with 6 SSDs.

Direct-Attach SSD Storage - Performance & Comparisons