Time machine and Raid 0 problem?

Discussion in 'Mac Basics and Help' started by chrono1081, May 27, 2008.

  1. chrono1081 macrumors 604

    chrono1081

    Joined:
    Jan 26, 2008
    Location:
    Isla Nublar
    #1
    Yes I know its bad to use raid 0 but I was using time machine just to try it out and backups will backup once or twice, then all of the sudden time machine will freeze, and the drive will no longer be recognized, and then the drive is hell to get working again. I have to plug it into a windows machine and use a norton tool to initialize it, and reformat it in ntfs, then reformat it in mac to make it useable again.

    I know everyone will say its the hardware but I assure you it is not. This happens with every drive I try, and every raid enclosure I try and it only happens in mac with time machine (and I tried reformatting the mac). Is there a known problem with time machine and raid 0? I searched the forums and didnt see anything. Anyone else have this problem?
     
  2. merl1n macrumors 65816

    merl1n

    Joined:
    Mar 30, 2008
    Location:
    New Jersey, USA
    #2
    How are you reformatting it in a Mac? Just erasing the disk is not sufficient as a reformat if you initialized it on a pc. You must go into Disk Utility, select the disk (not the volume beneath it), go to the Partitions tab, change the "Current" scheme to "1 Partition", click the options button, select GUID Partition map, click apply, name the disk and click OK button. Then the disk will be reformatted with the correct mapping.

    If you are going to use RAID 0, you must do the above on both disks and then set up your RAID pair. You will not see any real performance boost from using RAID 0 in this fashion since you are using the same bus to write to both disks.
     
  3. chrono1081 thread starter macrumors 604

    chrono1081

    Joined:
    Jan 26, 2008
    Location:
    Isla Nublar
    #3
    Thank you for the suggestion. It's been awhile since I set it up on the mac so I don't remember if that is what I did or not. I will try that tonight though and see how time machine does. I would really like to have my 1.5 tb drive (two 750's) just for time machine since I have some very very beefy files :D
     
  4. merl1n macrumors 65816

    merl1n

    Joined:
    Mar 30, 2008
    Location:
    New Jersey, USA
    #4
    You would be better off with RAID 1 (mirroring) if you value your files. This way if you lose a drive, you are still protected.

    I have Terabites of video (I'm a videophile) and there is way too much to even consider backups. So all of my drives are mirrored.
     
  5. chrono1081 thread starter macrumors 604

    chrono1081

    Joined:
    Jan 26, 2008
    Location:
    Isla Nublar
    #5
    I completely agree with mirroring. I use it on all of my permanent stuff that I want to keep. Time machine I am not hugely concerned with its just kind of an extra and thats all this drive is for. I'll fill it up in a few months anyway.

    Well, it looks like your suggestion worked *knock on wood* but I will post it here so anyone with a similar problem can search the forum and find it.

    I was using a raid external enclosure and on the enclosure you can choose what raid you want. Well, I chose stripe, and reformatted using macs file system (the way time machine makes you) then when I would use the drive and there would be huge problems after a little bit of use, so here is the fix:

    -On the raid enclosure I set the disks to "individual" verses raid so that when plugged in the machine saw two individual drives.

    -I then used merl1n's suggestion on how to format the disks. Each disk was reformatted individually to the mac file system.

    -Then, under Disk Utility, use THAT to create your raid array. Mac now sees the two drives under disk utility (verses just one) then it also sees the 1 big drive created out of the raid array.

    Thank you so much for the help :)
     
  6. merl1n macrumors 65816

    merl1n

    Joined:
    Mar 30, 2008
    Location:
    New Jersey, USA
    #6
    Whoa. I thought you were using two separate drives (2 enclosures). You never mentioned that this was a single raid enclosure.

    You didn't need to change the RAID scheme on it. If it was set to RAID 1 you should have left it alone. The only thing you needed to do was Reformat (Partition tab) the drive (striped drives as one drive) using the GUID partition mapping as I instructed you before.

    This was an important detail you left out. There was no need for you to use Disk Utility to set up a RAID scheme.

    I have a 1.5TB drive enclosure (has two 750GB drives striped) for TM backups and the OS sees it as one drive. No need for RAID0 since in essence it already is via Hardware RAID in the enclosure.

    I think you should revisit this as you have made your setup more complicated than what it should be. You are defeating the hardware RAID in your enclosure.
     
  7. merl1n macrumors 65816

    merl1n

    Joined:
    Mar 30, 2008
    Location:
    New Jersey, USA
    #7
    Sorry, I made a typo:

    should read: RAID0
     

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