Move RAID0 slice to new drive

Discussion in 'Mac Pro' started by digitalhen, Sep 16, 2011.

  1. digitalhen macrumors regular

    Jan 10, 2006
    Hi folks,

    I have a RAID0 in my 2010 MP, consisting of 3 drives. I'd like to move one of the slices to a new drive (moving from a WD Green drive, to a Black Caviar).

    Is it possible to do this without creating a new RAID0 from scratch? Can I boot the computer from the start up disks and just clone the drive?

    Cheers in advance.
  2. nanofrog macrumors G4

    May 6, 2008
    If I understand what you're trying to do properly (swap an existing member <disk> for a different disk), then the answer is unfortunately NO. :(

    You'll have to do the following:
    1. Make a backup of the existing RAID 0 set
    2. Add the new Caviar Black disk/swap it for the original Green
    3. Go into Disk Utility, and make a new set of the disks you want to use
    4. Restore the data from the backup you made
    At this point, the new set is ready to go and contains all of the data of the original set.

    As per the Green drive, it will need to be reformatted prior to using it.
  3. JavaTheHut macrumors 6502


    Aug 15, 2010
    Out of curiosity why would the duplication of 1 <disk> to the New <disk> fail?
  4. nanofrog macrumors G4

    May 6, 2008
    The cloning software doesn't work at a low enough level to perform proper clones of individual members (essentially, it doesn't know what the stripes are, and doesn't know what to do with them, as either the system + software or hardware RAID card handle putting them together into readable files).

    You can however, clone an entire array so long as the target volume is large enough = same capacity as the set or larger (higher level data transfer at this level, so the data is copied correctly). Particularly for data arrays (some clone applications still have issues with bootable volumes from what I recall, though it's not universal).

    Acronis for example, will clone bootable volumes, including RAID volumes, but it doesn't work with OS X at all (supports Windows and Linux file systems <FAT16/32, ext2/3/4, NTFS, but not HFS/HSF+). BTW, it actually does this by rebooting into a Linux Kernel before actually performing the clone operation.

    Not sure about CCC or SuperDuper, so they'd need to be checked out before attempting it for an entire RAID volume (recommended that the user still performs a backup before attempting to find out first hand, regardless of what information is available as things can go wrong).
  5. wonderspark macrumors 68040


    Feb 4, 2010
    Fortunately, since building a RAID0 set takes about four seconds, the fastest and most assured way of swapping in a new disk is to just nuke the set, swap the disk, and rebuild the RAID0 set. Copy your backup to new set, and *poof*... you're done!
  6. digitalhen thread starter macrumors regular

    Jan 10, 2006
    Heh - you make it sound so quick :cool:

    In addition to my Time Machine, I'm making an rsync backup of critical data. Copying 3 TB is quite slow :mad:

    Thanks for all the advice folks. I'm going for a dump and load.

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