5 Replies Latest reply on Mar 5, 2015 5:48 PM by LB@SDS

    H97 RAID 5 with five HDDs write performance issue?

    PetrJ

      Hello,

      I have MSI H97M ECO motherboard. My setup is:

       

      Intel Pentium G3420

      MSI H97M ECO

      4x 4GB DDR3 1600Mhz RAM

      1x SSD OCZ Vertex 4 128GB - for system

      5x 640GB WD Green WD6400AACS


      This is my home server hardware. I have Windows Server 2012 R2 installed.


      "First, I would like to inform, that I have green drives because of little noise and lower heating. I have been using them for several years and these are working very well and I don't have reason to change them. Capacity is enough for me. I have had been using just four of them, because I had MB with just 4 drives in raid support. Therefore I bought new MB, to be able to use all of them."


      This is my home server hardware. I have Windows Server 2012 R2 installed.


      My problem is with RAID performance.


      When I have all five drives in RAID 5, the performance is:

      R:300MB/s W:25MB/s (When I disable write cache, it is only R:240MB/s W:8MB/s)

       

      But When I setup RAID 5 only with four of them (any combination) the performance is OK:

      R:260MB/s W:240MB/s sequential

       

      Why is such a difference between 4 and 5 drives write speed? 


      Is there some limitation with Intel RST and amount of drives?

      I have noticed, when I configure RAID with five drives, it is initialized automatically. But with four drives, the initialization can be done later manually.

       

      I have latest version of RST and latest BIOS. The problem doesn't seem to be on the side of the motherboard manufacturer, but on Intel with H97 chipset.

       

      I appreciate any comment

       

      Thank you very much

       

      Petr Janousek

        • 1. Re: H97 RAID 5 with five HDDs write performance issue?
          PetrJ

          I have done some more testing. Here are ATTO Disk benchmark:

           

          1) RAID 5 with 5x HDD

                                               R5-5xHDD.PNG

          2) RAID 5 with 4x HDD

                                               R5-4xHDD.PNG

          3) RAID 5 with 3x HDD

                                                 R5-3xHDD.PNG

           

          4) stripe RAID 0 with 5x HDD - just for testing, if there is not some problem with five drives setup

                                             R0-5xHDD.PNG

           

           

          I have done testing with 3, 4 and 5 drives in RAID 5 configuration with write back caching. As you can see, there is really some problem with more than four drives. But with basic stripping is everything ok.

           

          It looks like there is some problem with parity calculations or caching.

           

          Thank you very much and have a nice day


          Petr Janousek

          • 3. Re: H97 RAID 5 with five HDDs write performance issue?
            PetrJ

            Hello @joe_intel,

            Thank you for the answer.

             

            But I the raid volume with five drives was completely initialized. It took about 16 hours. The benchmark was done after the initialization was finished. So there is no problem.

             

            I have tried two ways to configure RAID 5 with five HDDs:

             

            1) Clean setup - I have configured all five drives during configuration wizard, I have selected all space with 128kB stripe size. I was waiting about 16 hours to finish the initialization and after that was made the first benchmark in my first post (I have also tried NTFS format with different allocation unit size 4kB,16kB, 64kB). The result was about 25MB/s.

             

            2) HDD add - I have configured RAID 5 with four HDDs.  I have made second benchmark with 240MB/s write speed, after the initialization was completed. I have added the fifth drive to the volume and gave it time to finish the rebuild. The write speed was the same like after the clean setup with five drives. Only 25MB/s.

             

            On this picture you can see my raid setup with four drives, and with "Add disk" action I have added fifth drive.

            RST.PNG

             

             

             

            I have seen the tomshardware forum, but it is write back cache configuration and even only with three drives. It is not my situation.

            I found another person with similar problem on Z87 chipset.

             

            Thank you very much and have nice day

             

            Petr Janousek

            • 4. Re: H97 RAID 5 with five HDDs write performance issue?
              PetrJ

              I have done some more testing with the raid setup. Finally I found the solution with write performance. I have changed stripe size from 128kB to 32kB and write speeds are ok. joe_intel this is solution.

               

              I am on a write speed about 300MB/s and it is great

               

              Here you can see my RST volume setup and ATTO benchmark result:

              R5-wbc 32kB stripe size.PNG

               

              I would consider this behavior as a RST bug. But I am happy now.

               

              I hope, that this information will help somebody else in the future.

               

              Have a nice day

              Petr Janousek

              • 5. Re: H97 RAID 5 with five HDDs write performance issue?
                LB@SDS

                Does anyone here at Intel have any remarks regarding this bug?  I have struck this problem with 6 drives and had no issue with 5.

                We have a small run of prototype appliances here and are running into this issue on all of them!

                 

                This is a major issue as we may have to abandon the use of INTEL RST tech altogether.need that 128k Stripe on "X" number of drives like usual.