3 Replies Latest reply on Jul 25, 2012 3:24 PM by michael_intel

    Issue with SRT and RAID 5 on ASrock Z68 Pro3-M

    vladk2k

      Hello

       

      I have the following setup:

      • ASRock Z68 Pro3-M motherboard, BIOS version P1.70
      • RAID5 array composed of 2x WD1600AAJS 160GB SATA2 Drives + 1x WD2000JD 200GB SATA Drive
      • 90 GB OCZ Agility 3 SSD used as OS and Cache volume (Enhanced)

      This is a setup migrated from RAID1 + SSD. Here is a picture from IataUI:

      http://i.imgur.com/gxsMf.png

      Yesterday, while copying two large files (10GB each) from the SSD to the RAID5 Array, I noticed that the speed decreased continuously down to 18MB/s, which is less than in RAID1 and single disk setup. I went ahead and did some tests and this is what I've found:

      1. With SRT (Basic RAID5 performance):

      http://i.imgur.com/AI92a.pnghttp://i.imgur.com/01oZT.png

      2. With SRT (Enhanced/Maximized mode - doesn't matter, graphs are similar)

      http://i.imgur.com/GXRXP.pnghttp://i.imgur.com/GGrNr.png

       

      As it can be seen, write performance gets a big hit (and this is the same in maximized mode, which puzzled me greatly)

      Also, read performance seems to be less than half (I think the spikes in the file benchmark can be blamed to actual SRT Acceleration).

      I've seen the same low performance with RAID1, but there wasn't such a big gap between accelerated/not accelerated.

       

      So, what gives? Is RAID1-5 such a problem? Am I better off without SRT?

        • 1. Re: Issue with SRT and RAID 5 on ASrock Z68 Pro3-M

          Hello,

           

          Please be aware the Intel Rapid Storage Technology is a software RAID solution, which means that the data stripping is calculated by the processor and using the system resources, in addition the performance may be affected by the rest of the software running on the background, the performance test application being used, the type of memory and processor installed and also the settings of the performance tester which may have a big impact on the results.

           

          Further than this, I regret to inform you that Intel does not evaluate the performance of the specific RAID configurations used. In this case, if you have concerns about the performance and data transfers on your computer, please refer directly to your computer manufacturer.

           

          If you are doing performance measurements make sure you have the latest Intel Rapid Storage Technology at the link below:

           

          http://downloadcenter.intel.com/Detail_Desc.aspx?agr=Y&ProdId=2101&DwnldID=20624&ProductFamily=Chipsets&ProductLine=Chipset+Software&ProductProduct=Intel%C2%AE+Rapid+Storage+Technology+(Intel%C2%AE+RST)&lang=eng

           

          regards,

          Michael

          • 2. Re: Issue with SRT and RAID 5 on ASrock Z68 Pro3-M
            vladk2k

            Hi Michael.

            I am aware of the limitations of a software RAID solution, such as the one implemented by Intel in the Rapid Storage Technology. I was trying to raise awareness of an issue that affects a corner case scenario in the RST + SRT system, which is accelerating a RAID5 array.

            As I am sure you are aware, the SRT technology should provide better transfer rate & access time to pages of storage that have been cached to the SSD, while access to non-cached pages should intuitively remain the same. I have observed this to be true with a single disk, a RAID0 array and a RAID1 array. When the same tests have been done on a RAID5 array (namely, HDTune's read speed benchmark), the result was surprisingly different, as I have stated above.

            Is this normal behavior? Did the Intel QA team test such scenarios? Is it an incompatibility between HDD manufacturer, Motherboard manufacturer or SRT software?

             

            P.S.: I forgot to add that all drivers are updated to the latest available version, with the exception of the BIOS which, from what I can tell from the changelogs, does not improve the Matrix Storage functionality

            • 3. Re: Issue with SRT and RAID 5 on ASrock Z68 Pro3-M

              Hello,

               

              It is a normal behavior that a RAID 0 to provide better transfer rate & access time than a RAID 5, since a RAID 0 is known as a stripe set or striped volume, and RAID 5 uses block-level striping with parity data distributed across all member disks so it will take more time. The Intel Rapid Storage Technology, incompatibility between hard drives or the motherboard will not be a cause of the transfer rate & access time.

               

              regards,

              Michael