Mac Pro RAID (mirror) configuration

Discussion in 'Mac Pro' started by Grimace, Aug 27, 2008.

  1. Grimace macrumors 68040

    Grimace

    Joined:
    Feb 17, 2003
    Location:
    with Hamburglar.
    #1
    Hey all, I've not done RAID mirroring before and I ran into some trouble in Disk Utility. Here is what I want:

    Disk 1: Main drive (1TB)
    Disk 2: Mirror of Main drive (1TB)
    Disk 3: Time Machine (1TB)

    Some posts from the interblogz say that you cannot Mirror the startup disk. That doesn't seem to make much sense, but I'll believe it if it's true!

    When I tried to set up the Mirror in Disk Utility, I couldn't get the two disks to drag into a mirrored set.

    Any thoughts?
     
  2. Grimace thread starter macrumors 68040

    Grimace

    Joined:
    Feb 17, 2003
    Location:
    with Hamburglar.
    #2
    Bueller?

    Does anyone know if you can set up a mirror raid for the main startup disk?
     
  3. itsalan macrumors newbie

    Joined:
    Feb 5, 2008
    #3
    boot from your OSX install disk. Load up disk utility. You'll be able to create a mirror there with your startup disk.

    Note: this will wipe the data from the drives. You'll have to reinstall OSX after the fact.
     
  4. TranceMist macrumors newbie

    TranceMist

    Joined:
    Sep 4, 2008
    Location:
    Atlanta
    #4
    Use SuperDuper instead of re-install?

    I'm about to mirror my boot disks on my MacPro.

    But no way I'm going to re-install.

    My plan is to clone the boot disk to an empty disk in slot 3, boot from that disk, then wipe disks 1 and 2 to create the mirror.

    Then rather than re-installing OSX I plan to clone the boot disk back from disk 3 to the newly created mirror and reboot from that.

    Anyone tried it this way?
     
  5. yippy macrumors 68020

    yippy

    Joined:
    Mar 14, 2004
    Location:
    Chicago, IL
    #5
    I believe, (without any supporting evidence) that you cannot software raid the boot drive as the "raid" controller in that case doesn't load until after data must be read from the disk to boot the operating system and raid code.

    But you should be able to mirror the boot drive if you use a hardware raid card.
     
  6. Grimace thread starter macrumors 68040

    Grimace

    Joined:
    Feb 17, 2003
    Location:
    with Hamburglar.
    #6
    From this set of steps, I would just wipe 2 and 3 - RAID and wipe them, then clone 1 onto one of them. Fewer steps!
     
  7. itsalan macrumors newbie

    Joined:
    Feb 5, 2008
    #7
    As long as you use disk utility from the install disk to create the raid right before you install, it is possible. I've had a software raid 0 as the boot drive and accomplished it this exact way.
     
  8. TranceMist macrumors newbie

    TranceMist

    Joined:
    Sep 4, 2008
    Location:
    Atlanta
    #8
    RAID: YES, SuperDuper: NO

    I know for sure that software RAID on the boot disks is possible.

    The only question was the SuperDuper! method of avoiding re-install.

    I found an excellent article on MacWorld where the author tried this exact method and it didn't work. Having read the article and thought about it some more, I suspect it doesn't work because SuperDuper! ends up wiping out the the metadata which is stored on the disk to describe the RAID volume.

    However, rather than a complete re-install, I can re-install Leopard and run an upgrade from my cloned disk. Even though I won't really be "upgrading" versions (probably "downgrading" since my install disk will be older than my current Leopard), it should work. Then quickly upgrade back to current level.

    I may give this a try on a couple of spare disks (nothing to lose). If it fails, I go back to my original disk.

    If I don't like any of those options, I'm just going to do nightly authomated SuperDuper! clones of the boot disk to the other internal disk that would have been part of the mirror. It will accomplish nearly the same thing.
     
  9. MaddMacs macrumors 6502

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    Jan 16, 2008
    Location:
    Flagstaff, Az
    #10
    How about doing a restore from time machine after the raid is set up?
     
  10. Grimace thread starter macrumors 68040

    Grimace

    Joined:
    Feb 17, 2003
    Location:
    with Hamburglar.
    #11
    I finally have an extra 1TB drive to play with so I was thinking of trying to do my RAID 1 boot disk this week. Here is my setup and plan:

    1. 1TB drive (currently boot disk)
    2. 1TB empty
    3. 1TB empty

    I have a few other drives that have backup data on them, but for the moment we'll consider my setup to be three 1TB drives.

    1. In Disk Utility, set up a RAID 1 with two new drives.
    2. Carbon Copy Cloner (CCC) the boot disk info onto the new RAID 1
    3. Remove original 1TB boot disk from computer and see if it boots off of the new RAID 1 setup.

    Is it really that simple? Something tells me that I need to do something in the RAIDing process to make the disks "bootable".

    Any thoughts?
     
  11. PowerPaw macrumors member

    Joined:
    Jan 15, 2009
    #12
    Have you considered imaging your source drive using Disk Utility and then restoring the archive to your target mirror?
     
  12. Grimace thread starter macrumors 68040

    Grimace

    Joined:
    Feb 17, 2003
    Location:
    with Hamburglar.
    #13
    I think I would need an extra hard drive to do that, as the image would have to sit somewhere besides the boot disk or the two RAIDed drives.
     
  13. nanofrog macrumors G4

    Joined:
    May 6, 2008
    #14
    Do you know someone that has an external you could borrow?

    (As in, invite them over with the knowledge of what you're doing, and mention some tasty beverage, friend's preference of course, that might make it more tempting). They can see you won't abuse it, or hang on to it indefinitely. Could help. ;) :D
     

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