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Storage Upgrading to larger disks in RAID 5 array, need some advice

Discussion in 'Hardware' started by Bungletron, 1 Nov 2013.

  1. Bungletron

    Bungletron Well-Known Member

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    Hello

    I have 6TB RAID 5 array managed by a High Point RocketRaid 2680 card that currently uses 4 x 2TB disks. I was thinking I could upgrade all 4 disks to 3TB disks for 9TB total storage.

    I was thinking to upgrade the disks by degrading the array 1 disk at a time, adding each new 3TB disk and then rebuilding each time? Then after all 4 disks are upgraded and the array is rebuilt increase the partition size from 6TB to 9TB? I have the files backed up but want to avoid building a new array from scratch since it means configuring the network share all over again and it also takes ages.

    What do you reckon, is this reasonable or have I missed something, is this likely to have issues? I am confident one of you lot has the answer, cheers! :thumb:
     
  2. Margo Baggins

    Margo Baggins I'm good at Soldering Super Moderator

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    I'm pretty sure if you took a 2tb disk out of an array, put a 3tb disk back in and rebuilt it, it would treat it as a 2tb disk. But I might be wrong.
     
  3. saspro

    saspro IT monkey

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    I'd say you'd end up with spare space on the drives to create another array on.
    It's generally only things like SAN's & some NAS's that can expand
     
  4. droyden

    droyden New Member

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    Yep new array and migrate, degrading your array will potentially cause pain.
     
  5. asura

    asura jack of all trades

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    ZFS can do that... but I have no idea about a conventional RAID.
     
  6. droyden

    droyden New Member

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    If the raid card supports shrinking the existing array then that might be an option.
     
  7. Atomic

    Atomic Gerwaff

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    RAID5 does not support expanding an array, if you swap the disks for larger disks the array will not expand.

    Unless you're using another RAID type your only option is migrating the data off the array, destroying the array and creating a new array with the larger disks is the only option.
     
  8. droyden

    droyden New Member

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    OK I wasn't sure, you can resize a linux mdadm software raid online.
     
  9. Bungletron

    Bungletron Well-Known Member

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    will make a new array I think then, cheers guys!
     
  10. adrock

    adrock Caninus Nervous Rex

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    if you're running LVM on top of your existing raid 5 then I can think of ways of doing it without building the new array and migrating data, but i'd probably still choose to do the latter.
     
  11. Atomic

    Atomic Gerwaff

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    Yeah software RAID is a different kettle of fish to hardware RAID and often provides extra features outside the traditional spec of RAID, like being able to expand an array and change the RAID type.
     

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