5 Replies Latest reply on Jan 19, 2011 6:37 PM by asalcedo

    RECOMMENDED STRIP SIZE. 2 x X25-M 160 GB G2 RAID 0

    asalcedo

      I need to know what is the best strip size for my 2x X25-M 160 GB G2 Raid 0 on my Dell laptop M6500.

       

      The  laptop will be used for general web browsing, Microsoft Office, Photoshop, Visual Studio and other smaller programs.

       

      I tried 64 kb based on some research that I read some time ago. Then I read that 128 kb was better. I tried that and the boot up times were substantially better than with 64 kb. Which makes sense. Because booting up implies, I believe, large sequential reads, which are performed faster if the strips are of larger size.

       

      Now I read in the Intel Rapid Storage Technology Help that the default Strip size is 16 kB for Solid state disks, which seems to imply that 16 kB is the recommended one.

       

       

       

       

       

      RAID 0

      RAID 5

      RAID 10

      Default

      SATA disks

      128 KB

      64 KB

      64 KB

      Solid state disks

      16 KB

      128 KB

      16 KB

      Options

      4 KB, 8 KB, 16 KB, 32 KB, 64 KB, 128 KB.

      16 KB, 32 KB, 64 KB, 128 KB.

      4 KB, 8 KB, 16 KB, 32 KB, 64 KB.

       

      When I start the array configuration menu, the default Strip size shown is 128 kB, it does show the models and serial numbers of the drives, so the controller does know that they are SSDs, but the default strip size of 128 kB is very different from the 16 kB mentioned above.

       

       

      Thanks,

       

      Antonio

        • 1. Re: RECOMMENDED STRIP SIZE. 2 x X25-M 160 GB G2 RAID 0
          PeterUK

          When I start the array configuration menu, the default Strip size shown is 128 kB, it does show the models and serial numbers of the drives, so the controller does know that they are SSDs, but the default strip size of 128 kB is very different from the 16 kB mentioned above.

          The reason for that is you don't have the Rapid Storage Technology BIOS ROM which detects SSDs and uses the default listed for SSDs.

           

          The Intel RAID ROM can only be updated by a BIOS update from your PC maker.

          • 2. Re: RECOMMENDED STRIP SIZE. 2 x X25-M 160 GB G2 RAID 0

            Hi Peter,

             

            Thank you for your insightful comment.

             

            It makes sense that only a Dell Laptop BIOS update can update the Intel Rapid Storage BIOS ROM.

             

            It seems that Dell's BIOS does not have the latest Intel Rapid Storage Technology BIOS that identifies SSDs.

             

            Independently of that, and more importantly, do you then agree that 16kB is the Strip Size I should use for my array?

             

            I am thinking of making a disk image of my array into an outside USB drive and then reimage a 16kB strip Raid 0 array and test the difference but the disk transfer rates I am getting are so low that that will take days!.

             

            Thanks,

             

            Antonio

            • 3. Re: RECOMMENDED STRIP SIZE. 2 x X25-M 160 GB G2 RAID 0
              PeterUK

              Independently of that, and more importantly, do you then agree that 16kB is the Strip Size I should use for my array?

              Intel don't like to say why defaults are these defaults and may not apply to all HDD & SSD or how many you may have in a array, but one reason could be that a SSD can hit its sequential read/write speed on a smaller Strip Size then HDD can.

              • 4. Re: RECOMMENDED STRIP SIZE. 2 x X25-M 160 GB G2 RAID 0

                Based on my type of work, not database like, but more like sequential reading when launching apps, boot up and the like, I would tend to go for the larger strip size. This 16 kB comes to me as a great surprise that really makes me reconsider.

                 

                I find it almost unbelievable that there is no good information anywhere about such an important parameter for such a configuration, which, I know, is becoming very standard, 2x SSD in Raid 0.

                 

                And I do not understand why Intel has to be secretive or circumspect about it.

                • 5. Re: RECOMMENDED STRIP SIZE. 2 x X25-M 160 GB G2 RAID 0
                  asalcedo

                  Well, I still find it difficult to understand why this issue is not clearly answered.

                   

                  Anyway, I have now tried 16 kB and 128 kB.

                   

                  128 kB has given me better results in booting up and launching applications.

                   

                  I have then decided to use 128 kB stripe size.

                   

                  Antonio