8 Replies Latest reply on May 1, 2011 9:43 PM by

    Poor Raid 5 performance




      I have a SR1530HSH server with the following configuration : E5400 Dual core processor and 4 GB RAM (Smart-UPS keeps server up and shuts down nicely in case of power outage).


      I was running it with 3 pcs seagage 7200.10 250 Gbyte drives in a standard RAID5 array on windows server 2003 for a few years and after discovering write cache and enabling this the array performed as expected. I was getting about 120 Mbyte sustained read and less but ok write.

      Now i changed the drive out for 3 Seagate 7200.12 1 Tbyte drives and set the new array up with the same stripe size parameters and everything. I installed windows server 2008R2 on the machine, installed the newest available drivers ( and then the IRST program. After that i told IRST to initialize the drives which it took a full week to do and when it was finished i suddenly remembered the write cache option so i enabled this.


      But even with the write cache enabled i am getting really slow read/writes. In fact much slower than if i had just attached one disk and run it non-raid.


      Here is the IRST program screenshots :


      First one shows the raid :


      Second one shows one disc.



      As you can see everything looks just fine and the other 2 discs are exactly the same except for the serial (PS. I have upgraded firmware in the drives since i took these screenshots so now all discs are firmware CC46...Did not help though...)


      I made this test with ATTO benchmark and as you can see it is nowhere near the performance i would expect. I have read that software raid is not as good as hardware raid but surely i should see atleast the same performace as on the much older discs..




      Any help and ideas would be greatly appreciated.