iscsi on protected server -poor performance but JUST with DPM RRS feed

  • Question

  • Test environment of one protected server and one DPM server

    Protected server is a file server (2008r2) C: drive (80GB mirrored sas) & d: (3Tb iscsi drive on ax4-5i). In production only the D: drive is being protected.

    The same 5GB folder ("test_data") exists on both C: drive and D: drive on the protected server.

    When protecting JUST  the 5GB  "test_data" on C:, the initial sync takes 1min 37 seconds. 
    When protecting JUST  the 5GB "test_data" on D:, the initial sync takes 2 hours 10 minutes.

    but when doing  a simple standard file copy of the data from the protected server to the DPM.

    The 5GB on the C: drive copies across in 59 seconds.
    The 5GB on the D: drive copes across in 70 seconds. (slightly longer as would be expected)

    There appears to be something about the iscsi drive that is not agreeing with the DPM mechanism.  

    Any help would be appreciated.


    for the record, de-installing EMC powerpath fixed the problem. 

    (had to use MS own mpio in "fail over mode).

    EDIT 2:

    Due to the EMC using active/inactive SPs. MS MPIO would not work with some Virtual disks as it expected active/active.

    Turned out that If I went into powerpath 5.5 and on disks turned the policy from "claropt" to "request" the problems disappeared. Doing so loses load balancing (for smaller systems not really needed), but keeps redundancy.

    (I say all this not for a response, but for the sake of google)


    Wednesday, June 27, 2012 8:17 PM