IOPS performance on Dell EqualLogic

Question

Hi there, We have a PS 6100 with 24 SAS HD (10K 900GB) configured on a 50 RAID. I have proceeded performance tests to have an idea about max IOPS that the storage device can deliver. According to the theory, each hard disk can normally deliver about 140 IOPS. with 100% read, the max IOPS should be 140 x 22 (2 spare disks) = 3080 with 50% read and 50% write, max IOPS = 3080 * 50% + (3080 * 50% / 4) = 1925 When i use IOmeter, in sequential mode with 64k blocksize, i obtain : 100% read = 7300 IOPS 50% read / 50% write = 7000 IOPS (5000 / 2000) SAN HQ displays the same values. How comes this huge difference ?

desperadeo · Answer

Hello Donald,

My storage device is only used for my vSphere platform and the average size of block (displayed by SAN HQ) is :

64KB for reads
32KB for writes

With a 70%R/30%W workload.

If I understand your meaning, the IO performance is not only about the performance of hard drives but I need to take into account the storage controller, cache and software.

If a new project requires an estimated IOPS, how do I know that the storage device (bought in the future) would be able to deliver them without loss of performance ?

desperadeo · Answer

I already read this guide to configure our storage environment in order to obtain the best performances between the ESX hosts and the EQL devices :)

I can get the IOPS per volume with SAN HQ, can you suggest me a nice software which gives IOPS per VM ?

FluidFS

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