Quick RAID 1 question

Discussion in 'Mac Basics and Help' started by Blue Velvet, Dec 9, 2007.

  1. Blue Velvet Moderator emeritus

    Joined:
    Jul 4, 2004
    #1
    In Leopard's Disk Utility, can I add a new drive to an existing one that has data already on it which I wish to mirror, without erasing the data first?

    Would just like to double-check before I start messing with things that may not be able to be undone.

    Thanks for any help. :)
     
  2. robbieduncan Moderator emeritus

    robbieduncan

    Joined:
    Jul 24, 2002
    Location:
    London
    #2
    I don't use the software RAID in OSX, but I'm finding the question a bit confusing.

    You currently have a single drive with 1 partition that you want to turn into a RAID 1 (mirrored) set?

    Edit: Or do you want to add another mirror to an existing RAID set?
     
  3. Blue Velvet thread starter Moderator emeritus

    Joined:
    Jul 4, 2004
    #3

    I have a single drive with 1 partition that has data on it that I don't want to erase. I'd like to add another drive to that one and make a RAID 1 setup with the both of them, mirroring each other, without erasing the data on the first drive. Does that make sense? Is that even possible?
     
  4. robbieduncan Moderator emeritus

    robbieduncan

    Joined:
    Jul 24, 2002
    Location:
    London
    #4
    From my reading of the Disk Utility help that is possible with a number of caveats:

    You cannot create a RAID set using any partitions from your startup disk without first booting from another disk.

    You can either mirror at all times (RAID Slice) or mirror only when anther drive fails (Spare: I assume you only use this when you already have at least 2 RAID Slice).

    You have to choose Volume Format for the RAID set: this implies the system will re-format the disks so you would loose all data...

    The help page I am referencing can be found in Disk Utility help by searching for RAID and choosing "Creating a mirrored RAID set"
     
  5. Blue Velvet thread starter Moderator emeritus

    Joined:
    Jul 4, 2004
    #5
    Thanks, it's not a boot disk. I think I'll experiment with a couple of externals first before meddling too much. I owe you a pint of Guinness. ;)
     

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