VMAX Performance issues

Question

Hello Experts, We are trying to understand some of the performance benchmarch results that we have received from SQLIO test on windows 2012. test scenerio: A windows VM residing on FC pool and it has three drives (C,E,F) all in the same datastore.         C & E drives have same Allocation unit size (4K), C is MBR and E is GPT but as per SQL IO test, the throughput differs. C is slighly slower than E? Can we explain? F drive has 64K allocation unit and gives best results which is expected.                                                                                                                                                                                                                                                                                                                                                                                             Operating System Windows 2012 R2 Storage profile Silver File size for SQLIO 9 GB Disk layout: Drive letter StartingOffset Allocation unit size Partition type C: 1024 KB 4096 bytes (default) MBR E: 33 MB 4096 bytes (default) GPT F: 33 MB 64 kilobytes GPT Benchmark results: C: IOPS Throughput (MB/sec) E: IOPS Throughput (MB/sec) F: IOPS Throughput (MB/sec) Write - 8k random 20161 158 Write - 8k random 23905 187 Write - 8k random 25604 200 Read - 8k random 25501 199 Read - 8k random 27253 213 Read - 8k random 27293 213 Write - 64k sequential 8939 559 Write - 64k sequential 11905 744 Write - 64k sequential 14077 880 Read - 64k sequential 17317 1082 Read - 64k sequential 21320 1333 Read - 64k sequential 21731 13 regards, Saurabh

Quincy561 · Answer

Also if the tests are run separately,  you should allow time after a write test for the writes to destage before starting another test.

Quincy561 · Answer

Is every test run separately? Did you run each one multiple times to see if you always get the same results? Did you pre-write these devices?

Not sure what impact the offset or the partition type has.

Do you have some pre-set expectations for these tests or success criteria?

Symmetrix

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