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Thread: 10GbE iSCSI tuning

  1. #1

    Default 10GbE iSCSI tuning

    Poweredge 2900 running 2xDC Xeon, 10GB RAM, 6x7200RPM 2TB Drives, Perc6 w/512MB cache, RAID 10.

    Chelsio 10GBE adapters at both ends ESX 4.1.

    Currently, reads are only 150MB /sec, writes are 330/MB at 512k from inside a Windows VM. These drives in the same config will push 700MB/sec locally.

    4k are 16/17 respectively.

    The read writes seem backwards.....and I must be off in tuning something. I've followed the 4.1 guide and set all the params....they didn't do a thing.

    Any ideas?

  2. #2
    Join Date
    Oct 2010
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    Default

    check array write caching, and read caching is enabled.

    can try some tweaks on targets too:
    1. From the console, press CTRL+ALT+W,
    2. Select Tuning options -> iSCSI daemon options -> Target options,
    3. Select the target in question,
    4. change the MaxRecvDataSegmentLength and MaxXmitDataSegmentLength values to the
    maximal required data size (check w/ the initiator to match).
    maxRecvDataSegmentLen=262144
    MaxBurstLength=16776192
    Maxxmitdatasegment=262144
    FirstBurstLength=65536
    DataDigest=None
    maxoutstandingr2t=8
    InitialR2T=No
    ImmediateData=Yes
    headerDigest=None
    Wthreads=8

    make sure the software initators in vmware match these settings too.

    can also up to jumbo frames on the cards.

  3. #3

    Default

    Quote Originally Posted by Gr-R
    check array write caching, and read caching is enabled.

    can try some tweaks on targets too:
    1. From the console, press CTRL+ALT+W,
    2. Select Tuning options -> iSCSI daemon options -> Target options,
    3. Select the target in question,
    4. change the MaxRecvDataSegmentLength and MaxXmitDataSegmentLength values to the
    maximal required data size (check w/ the initiator to match).
    maxRecvDataSegmentLen=262144
    MaxBurstLength=16776192
    Maxxmitdatasegment=262144
    FirstBurstLength=65536
    DataDigest=None
    maxoutstandingr2t=8
    InitialR2T=No
    ImmediateData=Yes
    headerDigest=None
    Wthreads=8

    make sure the software initators in vmware match these settings too.

    can also up to jumbo frames on the cards.
    Yup already done. Its the read/write disparity that has me confused....

  4. #4

    Default

    Quote Originally Posted by dwright1542
    Yup already done. Its the read/write disparity that has me confused....
    So still getting VERY poor read performance. Write performance is very good.

    Does ANYONE have an idea, or do I go back to Openfiler? (I've now tried DSS 3 times, and have ended up back at OF every time)

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