SSD Performance in the vSphere Home Lab

crucial-resizeLast weekend I was poking around on the Newegg website and noticed that they were having a sale on Crucial SSD drives. I have wanted to purchase SSD’s for my ESXi host boxes but that was more out of a want then a need based on SSD pricing. That quickly changed after I found the Crucial M4’s 64GB on sale for $88.00 a piece (and now currently going for $79.99). I added them to my cart and proceeded to check out.

I received the drives on Thursday and brought down one of my hosts and swapped out the existing internal RAID 5 I was running for the SSD’s. I installed ESXi on one SSD and used the second as a dedicated datastore (this config is just for performance testing, each host will end up with a single SSD) to start some testing.

My ESXi hosts are whitebox machines made up of an ASUS P7F-E motherboard, Intel Xeon X3430 Lynnfield 2.4GHZ QC, and 16GBs of RAM. One draw back of my hosts is that the onboard SATA controller is only 3GBs where as the drives are 6GBs capable which will have in effect on my performance numbers.

For testing I created a new VM based on Windows Server 2008 R2 with 2GB of memory and a single vCPU. IOmeter was installed on the VM and I used the configuration provided from the “Unofficial Storage Performance” thread located HERE on the VMware Communities. Each test was performed three times and used the averages to populate the charts below. The tests where performed with the VM running on the same SSD as ESXi was installed (Shared Datastore) and the VM running on a SSD that was configured as a standalone datastore (Dedicated Datastore).

And now the results:

Shared Datastore
Test IOPS MBps Avg IO Response Time Max IO Response Time CPU Utilization
MaxThroughput 100% Read 4568.86 142.78 13.3 29.36 18.38
MaxThroughput 50%Read 2179.04 68.09 27.67 63.34 15.15
Random 8k 70%Read 2746.65 21.47 21.91 181.63 16.68
Real Life 60%Random 65% Read 2283.02 17.84 26.35 197.91 16.03
Dedicated Datastore
Test IOPS MBps Avg IO Response Time Max IO Response Time CPU Utilization
MaxThroughput 100% Read 4588.67 143.41 13.16 51.66 19.16
MaxThroughput 50% Read 2180 68.16 27.64 65.02 15.24
Random 8k 70%Read 2740.67 21.63 21.95 113.88 16.94
Real Life 60%Random 65% Read 2374.33 18.55 25.35 66.02 16.11

As you can see from the charts above the overall IOPS and MBps are about the same whether the VM was running on the shared or dedicated datastore. However, I was surprised by the changes in the Max IO Response Time numbers.

All in all very happy with the performance numbers I am seeing, and as the main goal was to replace the internal RAID5 on each host (mostly from a power consumption perspective) I am glad I made the purchase.

-Jason