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Thread: iSCSI performance unacceptable

  1. #1

    Default iSCSI performance unacceptable

    HP Microserver with 4 x Seagate 5900rpm drives set as two software raid mirrors, both MDx in a single Volume Group, one big iSCSI Target, Intel e1000 PCI-e card, dedicated to iSCSI network

    Attached to Win Server 2003 R2 via (also) dedicated iSCSI Intel NIC

    The iSCSI speed is awful (write ~ 25Mb/s)

    It is not Win Server 2003 fault, as is also connect via the same iSCSI network to Thecus i5500 unit

    OK, the Thecus has 7200rpm drives & build in HW RAID

    But the hardware is now 3 years old, yet it blasts write of excess 100 Mb/sec (that is at least FOUR times faster)

    What to do to improve the HP/DSS combo?

    Thanks

    sebus

  2. #2
    Join Date
    Aug 2010
    Posts
    404

    Default

    Do you have the latest build of DSSv6? as you may need a new driver for your RAID, so update to the latest build could help you to get the latest drivers needed.

    Also try to tune your system, you can find that in the KB at:
    http://kb.open-e.com/42/
    and
    http://kb.open-e.com/How-can-we-impr...eter_1083.html

  3. #3
    Join Date
    Oct 2007
    Location
    Toronto, Canada
    Posts
    108

    Default

    Sebus,

    I am not surprised that your performance is poor.

    The miniserver has just about the worse posible setup.

    You are using slow HDDs. The Seagate 5900 RPM drives have read and write seek times of 12 and 13ms, compared to 8.5 and 9.5ms for 7200 RPM drives, or 3.8/4.4 ms!! for 10,000 PRM drives.

    You are using *Software* RAID

    Further,

    The HP Microserver is running a generic AMD Athlon II CPU and generic Server NIC.

    Whereas, the Thecus devices is a *specialized IO processor* (Intel® IOP331 I/O) which has integrated RAID 6 and iSCSI CRC32C functionality.

    A specialized device will always outperform a generic one.

  4. #4

    Default

    NO, the HP does not run a generic NIC, as I replaced it with PCI-e Intel version, so I can get jumbo frames (the on-board Broadcom does not have jumbo frames)

    And what is wrong with software RAID?

    I am sure that specialized device will outperform, but 25Mb/s I can get on USB2

    On same hardware HP Microserver (with same drives, also softrware RAID, and even on-board Broadcom, as I did not yet swap it) with Openfiler 2.3 I can get FTP writes of excess 60 Mb/s

    And yes, I have the latest available version of DSS 6

    I do not expect miracle (like my Equallogic array), but twice the current speed would be more like what should be expected

    sebus

  5. #5

    Default

    Quote Originally Posted by Al-S
    Also try to tune your system, you can find that in the KB at:
    http://kb.open-e.com/42/
    I do NOT have AutoNeg parameter on that screen to edit

    sebus

  6. #6
    Join Date
    Oct 2010
    Location
    GA
    Posts
    935

    Default

    Try this:

    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 initiators to match).

    maxRecvDataSegmentLen=262144
    MaxBurstLength=16776192
    Maxxmitdatasegment=262144
    FirstBurstLength=65536
    DataDigest=None
    maxoutstandingr2t=8
    InitialR2T=No
    ImmediateData=Yes
    headerDigest=None
    Wthreads=8

  7. #7

    Default

    These settings do make the speed jump to a more acceptable 42Mb/s on write

    sebus

  8. #8
    Join Date
    Oct 2010
    Location
    GA
    Posts
    935

    Default

    At this point, without hardware raid, your at about the top for tuning your setup.

    With hardware raid, there are more things to tune for speeds.

    One other thing to use is block I/O and WT on the targets, if not already.

  9. #9

    Default

    For a D2D2T backup it will have to do, no space to fit RAID card

    Why these options are not default then?

    sebus

  10. #10
    Join Date
    Oct 2010
    Location
    GA
    Posts
    935

    Default

    Since the daemons that run the connections are open source, and we don't know with certainty what each system may involve, or hardware used, we stay on the defaults to start with.
    But for backups, that's not to bad really.

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