2 Replies Latest reply on Dec 23, 2010 2:14 PM by Dan_O

    Fast Write but slow Read performance on MFSYS25


      Hi all,


      I'm struggling with the <read> performance of the MFSYS25 while the <write> performance seems in line of what I'm expecting from our system.


      I've set up a raid10 array out of 8 disks just for testing purposes and doing simple benchmarks with large file performance (next will come bonnie).


      The problem I have is that write performance is around 270-290MB/sec while read performance is only 70-76MB/sec (i.e. slower than a single disk).


      I'm testing with a simple:


      # dd if=/dev/zero of=/mnt/shared/aaa bs=16M conv=fsync
      51+0 records in
      50+0 records out
      838860800 bytes (839 MB) copied, 3.06737 seconds, 273 MB/s


      # dd if=/mnt/shared/aaa of=/dev/zero conv=fsync

      1653896+0 records in

      1653896+0 records out

      846794752 bytes (847 MB) copied, 15.659 seconds, 54.1 MB/s


      Now... this is ridiculous and there must be something really bad going on.


      The system is a MFSYS25, latest firmware (6.6) and configured as follows:


      8xSeagate Constellation 2.5" 7200 SAS disks (model ST9500430SS, firmware 0003)

      single virtual pool and single raid10 disk for testing purposes.


      The server blade is a MFS5520VI with a single Xeon 5620 and 4GB ram (I'm focused on the disks atm).


      I would really appreciate any hints.