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    Intel RST RAID verification and repair

    slintel

      This Intel web page describes how Intel RST verifies and repairs RAID volumes:

       

      http://www.intel.com/support/chipsets/imsm/sb/CS-023081.htm

       

      It says that for RAID 1 and 10, RST does the following:

       

      "Data on the mirror is compared to data on the source. If the data on the mirror does not match the data on the source, the data on the mirror is overwritten with the data on the source."

       

      It says that for RAID 5, RST does the following:

       

      "Parity is recalculated and compared to the stored parity for that stripe. If the newly calculated parity does not match the stored parity, the stored parity is overwritten with the newly calculated parity."

       

      My questions are:

       

      1) For RAID 1 and RAID 10, what if it's the source that contains corrupted data - will it really copy that corrupted data onto the mirror, causing the correct data to be lost?

       

      2) For RAID 5, what if corrupted data was used to recalculate the parity - will it really overwrite the old correct parity with the new incorrect parity?

        • 1. Re: Intel RST RAID verification and repair

          Hello slintel,

           

          Let me help you.

           

          For RAID 1 and 10 It is correct what you are saying. If you are going to rebuild a disk using a new one, all information from the Existent RAID Volume Disk will be copied to the new disk including all files. If the Operating System In the existent volume disk s corrupted, all information will be mirrored to the new disk.

           

          For Raid 5 the volume will copy all files that are missing to complete the parity.

          Kevin M

          • 2. Re: Intel RST RAID verification and repair
            slintel

            For RAID 1 and 10, I understand if I am putting in a new disk, then it will have to copy all the data (even corrupted data) from the existing disk to the new disk.  But what if I have 2 drives in the array and just want to do a verify?  If the source drive has corrupted data, why can't the Intel RST detect that and copy the data from the mirror drive to the source drive, instead of from the source drive to the mirror drive?

            • 3. Re: Intel RST RAID verification and repair

              This is because Intel® Rapid Storage Technology will rebuild the array and structure from the existing one (depending on the raid type). So if a new drive is added to the volume, it will have copied the information from the other driver (existing driver on the RAID).

               

              Kevin M

              • 4. Re: Intel RST RAID verification and repair
                slintel

                What if no new drive is added.  There are only 2 existing drives, and you do a verify and Intel RST finds a data mismatch.  How does Intel RST know which drive has the correct data?

                • 5. Re: Intel RST RAID verification and repair

                  Based on internal algorithms on the software the Intel® Rapid Storage Technology knows where the data is but there is no record or visibility for the users to know what the location of the files is.

                   

                  Kevin M

                  • 6. Re: Intel RST RAID verification and repair
                    slintel

                    So will the Intel RST ever overwrite good data on one drive with corrupted data from another drive?  The web page indicates that it might, which would be very bad.

                    • 7. Re: Intel RST RAID verification and repair

                      It might because it is copying the existent data from the other disk so if the data is corrupted, all information will be copied as well.

                       

                      Kevin M

                      • 8. Re: Intel RST RAID verification and repair
                        slintel

                        So then the Repair feature might actually destroy data instead of fixing it.  That's really bad.  I will look into other RAID solutions instead of Intel's.

                        • 9. Re: Intel RST RAID verification and repair
                          geogherkins

                          Does Intel care to respond, or should everyone seeing this thread accept slintel's conclusion as accurate? I find it very difficult to believe Intel would simply surrender.

                          • 10. Re: Intel RST RAID verification and repair
                            mikec_intel

                            The Intel® RST repair feature erases the information of the faulty Hard Disk Drive first then it will rebuild the RAID configuration using all the Hard Disk Drives.

                             

                            Mike C

                            • 11. Re: Intel RST RAID verification and repair
                              MikeS1531

                              But when the copies of data on two RAID 1 disks are different, how can the software tell which is the correct data and which is the corrupted data?

                               

                              My situation is this...

                               

                              I've just added 2 HDDs to my PC, set them up as RAID 1, and copied 2TB of data to them.  I did a verify (but not repair) on the new RAID array, and nine hours later IRST reported that the array had three errors.  Then I did a verify and repair on the array, and nine hours later IRST again reported that the array had three errors.

                               

                              I was expecting the second V&R process to produce some sort of message/report telling me what happened.  Does the Verify & Repair process create a log somewhere that I can check to see if it actually did a repair?  Or do I have to do another verify and hope that nine hours later I'll be told that there are no errors?  Is it possible that the errors are on part of the array that doesn't actually contain data?  (The array is larger than 2TB.)  If so, is IRST smart enough to mark those HDD sectors as bad and prevent the system from trying to use them to store my data?

                              • 12. Re: Intel RST RAID verification and repair
                                MikeS1531

                                Further to my previous posting, I've done another verify (but not repair) overnight.  And this morning I find that the system has found seven errors. 

                                 

                                Either my brand new disks have problems, or Intel's 'fix' process is making matters worse rather than better! 

                                • 13. Re: Intel RST RAID verification and repair
                                  mikec_intel

                                  Hi MikeS1531,

                                   

                                  I will need more details about the issue and your system before giving to you a troubleshooting.

                                   

                                  Please download and run Intel® System Support Utility and send me the results. Also, take a picture of the errors and paste them to your post.

                                  Download Intel® System Support Utility

                                   

                                  Regards,
                                  Mike C

                                   

                                  • 14. Re: Intel RST RAID verification and repair
                                    MikeS1532

                                    Mike C,

                                     

                                    Thanks for getting involved.  I have downloaded and run the SSU, but it wasn't clear to me whether I was supposed to 'Submit' the info as the SSU requested, or respond via the forum, or attach the results in reply to the email I received from you.  I tried the latter, but my email (it went to webadmin@intel.com) was rejected.  Should I have sent my response to a different email address?

                                    Below is a screenshot of the display from the RST showing it had
                                    found 7 errors.  I can't send an image of the RST page that showed I had 3 errors before I tried the Verify and Fix -- I didn't try to capture that because I didn't know I had a problem at that time -- but I expect it looked the same except for having a 3 where the 7 is below.

                                     

                                    Intel RST Screenshot (After Verify & Fix) 160415.jpg

                                    The SSU produced an XML file that I have saved and attached to this posting -- it contains far too much info to try to add screenshots of it here

                                     

                                    I think I managed to submit the above screenshot and the XML file via the Customer Service website, and that has created Service Request 00507991 if that's of any help to you.

                                    The issue remains as described further above -- I had 3 verification errors in my RAID array before I asked the RST software to fix them and 7 errors afterwards.  Why might that have happened?  Do I have a problem with my array?  Is it likely to be unreliable?

                                    I look forward to receiving your thoughts.

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