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How much IO throughput we can get for 16 sas 15 rpm drives

  • October 13, 2010 at 4:44 am

    #225022

    Hi,

    We have dell equillogic PS6000XV SAN with 16 sas drives of 15 k rpm and having raid 10 configuration.

    Out of these 16 drives 2 drives are used as hot spares.Each drive has 419.19 gb space.

    I read in one blog that :

    IO throughput per spindle to be approximately 180 IOP/sec to achieve latency below 20ms :

    For 12 disk RAID10 sets will sustain ~2160 IOPS/sec

    In my configuration what will be the IO throughput ?

    Thanks,

    Vamsy

  • October 13, 2010 at 6:41 am

    #1236130

    Please help me on this.

    Thanks,

    Vamsy

  • October 13, 2010 at 6:44 am

    #1236134

    download a free tool call SQLIO and test. This tool will measure your maximum throughput

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  • October 13, 2010 at 7:54 am

    #1236209

    15K rpm sas disk can reach 150-180 8k random IO/s per spindle in full stroke and about 90 - 125 MB/s for sequential access.

    So if you have 14 disks you should be able to reach 2300 8k IO/s in read (half in write since it's raid 10) and 1.5GB/s in sequential read (half in write).

    That is maximum theoretical performance, you'll get less depending on outstanding IO, packet size, mixed load and the millions things between your CPU and the spindle.

    Regular HBA card are limited to 400MB/s so don't expect to see this 1.5GB/s anytime soon.

    If you hit the SAN cache you'll see much better figures, but you shouldn't rely on it.

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