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Intel RST RAID-0 recovery

Alastair Grant | Saturday 3 October 2015

I decided to update my BIOS to see if would resolve a few bugs. To my dismay both of my two RAID0 stripped arrays weren't working.

It's normal for your computer to lose the RAID setting in your BIOS during an update, but setting it back to RAID from AHCI usually is enough for the array configuration to be recognised. For some reason this time it didn't. One disk of each of the arrays were listed as members, the others not.

Fortunately for me, my primary boot drive is a single PCIe SSD, so my OS would still boot fine. Running Intel RST (Rapid Storage Technology) in Windows listed the same error for each array:

Your volume appears inaccessible.  Try fixing any problems reported on the array disks.  If this fails, review the Troubleshooting section under Help for more information.  In all cases, back up any accessible data before taking action.

Unknown disk on Controller 255, Port Unknown:  Missing

Of course, being sensible computer users, you'll have a backup of all the data on those drives - but it's always a hassle recovering data, for one, it takes an age when you have large disks.

Fortunately there is a quick fix. It seems this doesn't work for everybody, and it's likely to be entirely down to what caused the error in the first place.

If your data is critical, then use a disk-imaging program to clone all your physical drives at block-level. You then have a backup just in case you muck things up, or it doesn't work for you.

  1. Go into your BIOS and take a note of your array settings (e.g. stripe size)

  2. Delete the array volume, casually dismissing the horrific notice that all data will be lost (it won't, just information about the array is lost, it doesn't actually write to your disk)

  3. Recreate the array volume with the exact same settings, being sure to add the disks back in in the same order as you did originally

  4. Boot into your OS and run TestDisk (if you haven't come across this before, keep a note of it, it's wonderful)
    1. Create a new log file 
    2. Identify and proceed with your array volume (not one of the member disks), which will be listed as /dev/sd?? whether you're on Linux or Windows 
    3. Select your partition type, which will probably be EFI GPT, or if on an older system, Intel 
    4. Select Analyse 
    5. Select Quick Search 
    6. It's likely it'll sit analysing cylinders - it won't find anything. Select Stop 
    7. Select Deeper Search 
    8. Hopefully your partitions will appear reasonably quickly in the list - select Stop when they do 
    9. Use the up/down arrows to select your partitions. 
    10. You can use "p" to view files on that partition; but generally you want to use left/right arrows to select the partition as primary (or whatever status is correct for that partition) 
    11. Once all partitions have been configured, press Enter to continue 
    12. If you're happy with the structure, select Write 
    13. Dismiss and exit the application
  5. You can now reboot your computer and your array should be back to normal as if nothing had happened.



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