On 22/05/12 13:44, Fletcher Cocquyt wrote:
Welcome to the dollars for IOPS game ! Assuming a 20ms response time threshold - 15K RPM SAS can deliver 220 IOPS vs SATAs 44 IOPS (about 5x) So SAS will get you the IOPS your VMs need.
It turned out that two DS14mk4 trays of 600GB FC was not much more than two DS14mk2 trays of 2TB SATA. SAS turned out to be way cheaper than 12x600GB 15krpm SAS disks, I think mostly due to the cost of the ATTO 6500N FC-SAS bridges required for a metrocluster. It's not actually installed yet, so I can't give you actual performance comparisons.
Speaking of metrocluster and SyncMirror, I'm going to reassign the old SATA disks to the other head and add them to its SATA aggregate. What's the best way to reallocate volumes that are being SyncMirrored?
Also which VMs are hogging the IOPs? You can download a free trial of vCenter Operations and see via the VM IO heat maps which VMs might be moved to local disk on the ESXi hosts (to offload the netapp)
While waiting for the disk to arrive, we put 6x 256GB OCZ Vertex 4 SSDs into a RAID 5 and put the most important SQL server on that, which is performing adequately ;) Since we don't use SMSQL I'm just using OSSV to backup the native SQL backups.
Having used vCOps for a while, I'm don't think I'd pay retail price for it.