4 Replies Latest reply on Aug 26, 2011 8:38 AM by Docent

    MFSYS25, SATA drives and performance questions




      I have MFSYS25 chassis with 14 x 2,5" SATA drives and one SCM. Currently there are 4 x RAID-5 storage pools, each contains one virtual disk and each is assigned to all four compute modules (so Shared LUN is used). When one disk fails, performance is unacceptable - not only the degraded pool is slow but all disk I/O operations on every pool are heavily affected. I would appreciate if someone could give me a few hints:


      1. Rebuild operation of a RAID-5 pool that consists of 3 x 500 GB disks takes about 30 hours to complete. It's very long. Can I do something about it?

      2. Maybe adding a second SCM would make the rebuild process faster?

      3. ...and/or maybe it would make the every day operations faster while one storage pool is degraded and being rebuilt?

      4. Disks are currently running as "unsupported" because I don't have AXXTM3SATA connectors. Would adding such connectors change anything in terms of performance during normal operations and/or rebuild process?

      5. Is adding these connectors mandatory to operate in dual SCM configuration?


      Thank you very much for any hints


      Best regards,


        • 1. Re: MFSYS25, SATA drives and performance questions

          The only way I know to speed up a RAID rebuild, is to shut down all other Compute Modules that access that Storage Pool, which is usually not worth it.


          Adding a second SCM would not make the rebuild go any faster, if you're still sharing VDs in the Storage Pool with Shared LUN


          Since you're not using the correct connector, how are the SATA drives attached?  SATA drives are much more susceptible to vibration than the normal SAS, which is why you have to have the new power supply and fan modules listed at http://www.intel.com/support/motherboards/server/mfsys25/sb/CS-031001.htm, that have less vibration.


          If the drives are not set up properly, too much RVI makes for a lot of write failures and retries, which would slow everything down.

          1 of 1 people found this helpful
          • 2. Re: MFSYS25, SATA drives and performance questions



            Thanks for your answer. I bought MFSYS25 about 3 years ago when SATA drives were not supported yet in any scenario. So all my components must be then dedicated to SAS only - I use standard brackets and standard fans and power supply modules. I don't have any special connectors for SATA disks, they just fit.


            It makes sense what you say, however I'm wondering how much would it help if I used AXXTM3SATA brackets + connectors but the same fans and power supply modules as I use now. In others words, maybe these special SATA brackets would manage to absorb most of the vibrations you are talking about? Changing all the equipment like fans and PS unfortunately rises the bill a bit...




            • 3. Re: MFSYS25, SATA drives and performance questions



              I have a customer in a likewise predicement.


              They have the original MFSYS25 chassis and would like to use Intel 510 SSD drives to enhance the performance of their terminal servers running on the blades.


              What has been your experience so far?


              best regards


              • 4. Re: MFSYS25, SATA drives and performance questions



                It's been some time and we decided to buy the SATA-SAS connectors for all disks. However, after several months, I can tell you there is no, absolutely no difference in our case.


                - disks are still visible as unsupported because of invalid fan modules and power supplies

                - performance was not changed in any way

                - our disks failure rate is at the same level as before


                I can see only one benefit of having these connectors - you can use a dual SCM configuration. However we have only one SCM so I don't think it was reasonable after all for us to buy these connectors.