ESXi 5.0 VM Performance problems - suspect RAID controller or hard drives
Posted on 2012-04-13
Am using VMware ESXi 5.0 with a recently purchased Z68 based motherboard, an Intel i7 CPU (hyperthreading enabled), 16GB DDR3 RAM and an LSI MegaRAID 9265-8i RAID controller.
Plenty of processing horsepower, yet with only 2 VM's running - a 1 vCPU Win 7 32bit w/ 1.5GB RAM and a 1 vCPU Windows Home Server 2011 w/ 3GB RAM - system response time seems remarkably slow.
The vSphere client is only reporting that the VM's are using 400 - 600 MHz, out of a possible ~11,000 MHz available. Adding another core (2 vCPUs) doesn't make any noticeable difference. This suggests to me a lot of waiting for disk IO.
Looking at disk performance stats after a server start up and boot up cycle for both VM's, the max read rate is 7650 Kbps and the average read rate is 4440 Kbps. Latency is 20 ms on average and goes up to 60 ms.
The LSI MegaRaid 9265-8i controller I'm using supports SATA at 6Gb/s speeds and has 1GB of caching. Although my hard drives are not the fastest, they are SATA3 and I would have expected latency closer to 12 ms on avg and perhaps more throughput? Certainly I would have expected better overall performance out of my ESXi server.
Problem is, I'm not sure what I should be getting and where to look other than at the disk sub system for performance problems.
Ideally I would like stats others are getting from the same or similar class of controller and advice / places to look for more speed and/or sources that would be causing performance bottleneck(s).