Rebuilding RAID 5 with bigger disks?

Discussion in 'Digital Video' started by gameface, Sep 28, 2010.

  1. gameface macrumors 6502

    Joined:
    Sep 11, 2010
    Location:
    Boston, MA
    #1
    I couldn't really find a place to ask this and since most video professionals use RAID arrays I figured this would be an OK place to ask.

    I have a 4 bay RAID5 enclosure that has 1.5TB drives in it. Can I take one drive out, and swap in a 2GB? Let the RAID rebuild and then do it with the next drive and so on until all 4 are swapped out? Once all 4 are swapped would the RAID be recognized as 6TB instead of 4.5TB?

    It seems like this would work, but I don't want to go mucking around with something potentially dangerous to my storage as all the media in this enclosure is vitally important to my business.

    Thanks!
     
  2. Phutchi macrumors member

    Joined:
    Jun 28, 2007
    #2
    I had to double check.

    No you can't rebuild your raid 5 array this way. You will need to migrate all data off the array, put in the new disks and create a new array, then transfer all data back onto it.

    some hardware based raid systems will allow you to increase the size of the volume by adding new drives to open ports (Raid bays) but i do not think any of the stand alone 4 drive units can do this.

    What you are wanting to do can be done with the Drobo. Any size disk can be used. Need more space toss in larger drives 1 at a time. We have the 8 bay pro model in one of the departments here and it makes increasing/managing storage so much easier.
     
  3. KeithPratt macrumors 6502a

    Joined:
    Mar 6, 2007
    #3
    Yeah, I really don't know, but I would have thought the issue would be that if you replaced a 1.5TB disk with a 2TB, given the way RAID5 maps itself out over sets, the rebuild would only be able to make use of 1.5TB on the new disk. What could it put on the additional 500GB that the rest of the set could keep in RAID5?
     
  4. gameface thread starter macrumors 6502

    Joined:
    Sep 11, 2010
    Location:
    Boston, MA
    #4
    That's what I was getting at. Replacing one drive, that 500GB would be lost. But, I assumed (I see incorrectly) that if I one-at-a-time replaced all 4 drives with 2TB then the extra 2TB gained overall would add the additional 1.5TB to the complete array. Guess I will have to wait until work slows down a bit and I can copy all the media to external drives and rebuild with 2TB drives. oh well...
     
  5. martinX macrumors 6502a

    martinX

    Joined:
    Aug 11, 2009
    Location:
    Australia
    #5
    The only time I have had anything to do with RAID 5, I went from 4 GB to 18 GB (yes, you read that right... and this unit served a department of 20) and simply popped out a 4 GB drive and replaced it with the larger one at 5 p.m.

    Repeat for two more nights. Done.
     
  6. UWF404 macrumors regular

    Joined:
    Jan 6, 2004
    #6
    What you describe can be done with a Netgear ReadyNAS. The ReadyNAS Ultra 4 (4 drives) can do this using Netgear's X-Raid system. Basically, you can hot swap and insert larger drive.
     
  7. martinX macrumors 6502a

    martinX

    Joined:
    Aug 11, 2009
    Location:
    Australia
    #7
    I know you trust us and all, but something that is vitally important to your business probably shouldn't be entrusted to a forum reply that takes your fancy.

    • check the manual
    • check the dealer
    • check the manufacturer's website
     

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