I was reading a post on a blog the other day from someone in the storage world, I forget what the site was now but something he wrote stuck in my mind.
” Application performance is determined often by Storage performance “
No matter where you look these days organizations are Virtualizing and Consolidating systems, it doesn’t matter what the application is…SAP, EXCHANGE, SQLSERVER people are virtualizing everything.
Last year while implementing a NS20 (CX3-10 back end) I found out the hard way that RAID 10 could only be presented to Fibre connected hosts and could not be presented via NAS.
I was talking to a colleague about this not long ago when he mentioned he’d heard the new NS120 we just implemented could now present RAID 10 via NAS…….so off I went to PowerLink and downloaded the latest NAS support matrix document and to my delight he was right.
One of the challenges implementing these kinds of systems is getting everyone to agree on how the storage should be configured, alot of people will lean towards 4+1 Raid 5 or 8+1 raid 5 to get the most bang for their buck while database administrators will typically request luns that reside on dedicated RAID 10 groups for the SQL logs and TempDB.
Regardless of which you decide to use, at least now you have the option. VMware’s storage vmotion makes it so easy to move the underlining vmdk files between luns on different raid groups to see how this effects performance of the databases or applications.
There is no doubt in my mind that virtual machines with logs and TempDB on RAID 10 will perform better, but for just a little perspective on this topic and mainly due to budget constraints we have our internal virtual environment sitting on a NS20 with only RAID 5 configured, we have roughly 25 production virtual machines including SQL and EXCHANGE for about 25 staff members all presented via iSCSI and it runs very very well.