Insights into EMC performance

Last week at the EMC conference I got a lot of new information, particularly from the performance engineers and their presentations. Unlike a lot of EMC contacts, they never hinted that they wanted me to ‘buy more disk”.  The big insight was that to get the best performance, you need to spread the work over all the spindles. No segregating different applications or different pieces of the applications. By including the whole frame in your stripes, you can hit all the spindles. So every app benefits. Contention is not a big issue because of the sheer  number of spindles, all lightly touched. The other eye opener was the proof that raid 5 is faster than raid 10. I always knew that was the case for reads, but they showed that they could saturate the write cache and still get the same write speeds as mirrored disk. Up till now I have used mirrored disks for everything and also segregated the workload on different disks. This next SAP hardware refresh is going to be all raid 5.


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