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sanman999

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13 years ago

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sanman999

10 Posts

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3645

November 6th, 2013 07:00

Vmax Performance issue.....BE high utilization

The backend of 4 engine 4 bay 240GB cache Vmax is very very high and this frame is very high i/o frame. Is there any work around for better performance on this frame.

DA utilization.JPG.jpg

  • Quincy561

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    Posted November 6th, 2013 09:00


    Lower the workload (Host IO limits?)

    Add more hardware

    Change raid protection

    Without more information, these are common solutions.

  • sanman999

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    Posted November 6th, 2013 12:00

    What work around can be done immediatly(temporary) to improve the performance. We did an SRDF to this frame and cant take performance questions from app team.

  • Quincy561

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    Posted November 6th, 2013 14:00

    Not sure what the performance problem is, or if it even has anything to do with the backend or not.

    I would get a Symm performance person involved.  There should be local folks that can assist.

    Host IO limits could slow less critical loads if the workload is just too much.

  • Fenglin1

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    Posted November 7th, 2013 00:00

    Are you able to identify which host consume much resource? Comparing the IOps and MBs/sec, greate than 100KB IO occurr from you APP server. I suspect there are Apps has big I/O which utilize much backend resource. Maybe writing lot of data which cause Cache WP% is high.

    I'd like to indentify the hosts and apply hostIO limiatation function may help temperary and follow Quincy56's suggestion to engage EMC local team for next steps

  • apethe

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    Posted November 8th, 2013 09:00

    I am having the same problem. BE utilization and response time is high. There is no SRDF. Please suggest a fix.

    Capture2.PNG.png

  • Quincy561

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    Posted November 8th, 2013 10:00

    it can be difficult and time consuming to try and solve performance problems here.  I would suggest a CS performance case be opened with EMC.  It sounds like there is too much workload going to too few SATA drives from what you have described.

  • apethe

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    Posted November 8th, 2013 10:00

    microcode is 5876.229.145. the application team is complaining of degraded performance since we migrated to the vmax. they have response times around 200ms for the sata disk group.

    as for the 3 'fixes':

    host io limits are set as per emc recomendations

    we cannot add more hardware

    sata is at r6

  • Quincy561

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    Posted November 8th, 2013 10:00

    Apethe, what code is the box running?

    With 5876.229 the DA % busy may be reporting higher than what should be reported.

    My first post suggested 3 "fixes".

  • apethe

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    Posted November 8th, 2013 11:00

    i am seeing the same load on all sata disks Capture 2.PNG.png

  • Quincy561

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    Posted November 8th, 2013 11:00

    Just because it is the same load to all drives doesn't mean it isn't too much.

    Figure each disk can do 50 IOPs with good response time.  Each host write = 6 disk IOs.  So you can figure out how many SATA disks you need pretty easily for your specific workload.