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MD1000 slows way down on large file transfers

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MD1000 slows way down on large file transfers

This question has been answered by DELL-Daniel Ca

We have two MD1000 SAS storage arrays hooked up to a Dell R710 server.  During a large file transfer (40+ GB) to one of the MD1000 arrays it will slow way down to a crawl.  It looks as if it is slowing down at the same spot every time we attempt to transfer a file.  The other MD1000 that is hooked to the server has no problem with file transfers.  This only happens when we copy to the MD1000.  Copying from the MD1000 works as it should.  Smaller file transfer copy fine.  The Dell Sever Manager shows no errors with any of the hardware.  PERC card batteries do not show low or bad.  Any suggestions appreciated!

Verified Answer
  • Hello, jsalyer350.

    It sounds to me like your PERC could be set in 'Write Through' mode -- where the data is passing the cache, and being written "through" to the disks. This can be VERY time consuming, in that you're waiting for actual moving parts. The PERC would need to be set to "Write Back" mode, where you can make use of the cache, and have an even stream of data to the disks.

    The PERC can be put in 'Write Through' mode if the battery fails, looses the charge capacity to contain the cache, etc. It may be that the battery lost charge, and then was recharged, but the setting never changed.

    You should find this setting in OMSA, if not post back and let me know.

    I hope that helps. Have a great rest of the week.

All Replies
  • Hello, jsalyer350.

    It sounds to me like your PERC could be set in 'Write Through' mode -- where the data is passing the cache, and being written "through" to the disks. This can be VERY time consuming, in that you're waiting for actual moving parts. The PERC would need to be set to "Write Back" mode, where you can make use of the cache, and have an even stream of data to the disks.

    The PERC can be put in 'Write Through' mode if the battery fails, looses the charge capacity to contain the cache, etc. It may be that the battery lost charge, and then was recharged, but the setting never changed.

    You should find this setting in OMSA, if not post back and let me know.

    I hope that helps. Have a great rest of the week.

  • PERC setting was set to "Write Back" but I went ahead and applied the setting anyway.  That fixed my problem.  Copy speeds are normal now.  

    Thanks for the help!

  • Outstanding! Glad I could help. Have a great rest of the week!