5 Replies Latest reply on Jul 23, 2010 4:23 PM by nataSofCols

    Slow Write Performance on RAID 5 (DP55WB)


      I have a home server running on a DP55WB board.  My system drive consists of 2x74 GB WD Raptor in a RAID 0 and 4x1 TB WD Caviar Black in a RAID 5.  The Raptor setup is fast with both reads and writes and the Caviar setup is fast on reads.  My problem is the writes to the Caviar seem to start off fast and then slow to a crawl.  For about the first 2 GB of the transfer, I'm getting around 130 MB/s+, but shortly after that, I just stops.  When I watch the throughput on the drives it actually stops writing for a bit, then takes a little data and stops again.  My transfer speeds, per Windows, drop down to below 3 MB/s and don't seem to recover.


      I'm not sure what I can do to fix the issue.  I have the same Caviar drives in my main system (only 2 in RAID 1) and they work great.  I've tried using the built-in driver and the latest driver, both giving the same result.  I just reloaded and went from Server 2008 to Server 2008 R2, once again resulting in no difference.  Any input/suggestions will be appreciated.


      RAID 5 Array Settings:

      Disk Data Cache - Enabled

      Data Stripe Size - 64 KB

      Write-Back Cache - Disabled