RAID setup not working :(

Discussion in 'macOS' started by ironsidephoto, Aug 16, 2011.

  1. ironsidephoto, Aug 16, 2011
    Last edited: Aug 16, 2011

    ironsidephoto macrumors member

    Sep 22, 2007
    All right. Here goes:

    I bought two Seagate Barracuda Green 2TB 64MB 5900RPM internal hard drives and a Rosewill R2-JBOD Aluminum 3.5" USB 2.0 DUAL-BAY External Enclosure from Newegg to use in a RAID 1 mirror setup to use as a photo storage system. I set them up in RAID using OS X Disk Utility (27" iMac running Lion). At first everything was fine. A few days later, I get an error message in Disk Utility saying that one slice (drive) of the RAID setup had failed and so the RAID was degraded. After ejecting/remounting etc that error went away and it said it was online and I could copy more files to it. Odd.

    A couple of days later I noticed the lost+found folder, and now when I turn on the drives, I get the error message pop up that says "This disk cannot be read by this computer" with options to Initialize, Ignore, or Eject. Initialize doesn't seem to do anything. However, in Disk Utility, it says the RAID is "online."

    What should I do? Do you think it's a drive error since I got the message saying that one slice was messed up before, even though now it says it's fine? (Verify/repair never showed any errors on any thing.) Or is the software RAID part messed up?

    Ugh. This is really important--photos are my livelihood.

    Terminal sez:

    AppleRAID sets (1 found)
    Name: MEGADUMP
    Unique ID: 4BA80F16-F7C8-43C1-A3E8-C7893672C8D3
    Type: Mirror
    Status: Online
    Size: 2.0 TB (2000054910976 Bytes)
    Rebuild: manual
    Device Node: disk5
    # DevNode UUID Status Size
    0 disk3s2 8DF2008A-8B5A-457F-9C3C-DFF387EF798B Online 2000054910976
    1 disk4s2 EC2DD19F-8D3C-452A-AD6A-1778EDAE5E8C Online 2000054910976

    It says everything is online, but when I turn on the drive it says it can't be used.
  2. WytRaven macrumors 6502

    Mar 19, 2009
    Orbiting Mercury
    Rule number 1: Don't use "green" drives in RAID. Those drives have variable spin speeds, aggressive sleep systems, and the like. If the controller doesn't understand that then you are asking for trouble.

    I know this doesn't really help solve your problem, sorry, but it might assist with not making the same mistake twice.
  3. ironsidephoto thread starter macrumors member

    Sep 22, 2007
    Actually, that does help. I hadn't thought about that...won't do it again.
  4. ironsidephoto thread starter macrumors member

    Sep 22, 2007
    The reason I wanted to do a mirrored RAID was instant backup of my data. If one drive failed while copying, the files wouldn't be corrupt on the other drive, I thought. If one drive failed even when not copying, I'd still have the other drive.

    Now I'm wondering if I should just use one of the drives as the storage, and use CCC or something else to do automated backups to the other drive instead of having them in RAID?
  5. larkost macrumors 6502a

    Oct 13, 2007
    I understand what you are trying to say here, but it must be said: RAID is not a backup. A backup provides you with a totally independent version of the files. A RAID (with some sort of mirroring) will protect you from a simple hardware failure (disk goes bad), but will do nothing for the rest of the cases where a backup will protect you:

    - The disk controller goes bad.
    - The filesystem goes bad (two copies of a bad filesystem still equal one bad filesystem)
    - You overwrite the good data with bad data (generational backups can help somewhat here)
    - A power surge takes out your drive (it is as easy to fry two drive controllers on the same circuit as one)
    - the list goes on...
  6. Foogoofish macrumors regular


    Jun 12, 2011
    I don't know what to suggest really other than:

    Take a hard drive out and try and single boot it in an external hard drive enclosure. This will most probably fail, but worth a shot.

    Also, if they are indeed your livelyhood, you need more than just RAID 1 backup. For a 3 person business startup, I am installing:

    2x RAID 1 750GB in Mac Mini server
    2x RAID 1 2TB in NAS
    1x Fire Proof out of office backup (location 1) - week 1+3 of month
    1x Fire Proof out of office backup (location 2) - week 2+4 of month
    Dropbox Storage of Admin files

    And this is just for a 3 person business. If they are really that important then you need multiple backups of backups of backups. You can never be too safe incase one part fails or becomes infected.

    ***School lesson over***
  7. maflynn Moderator


    Staff Member

    May 3, 2009
    Why not go with a full fledged NAS enclosure instead of a dual bay external drive?

    Going the NAS route provides you with the software to manage the unit, permissions, shares and has hardware RAID support.

    As the other posters mentioned, avoid green drives, RAID1 is not a backup, but just maintains data integrity.

    Personally I found QNAP to be an excellent product, another power player in the field is Synology. Both are highly recommended here and on the net.
  8. Foogoofish macrumors regular


    Jun 12, 2011
    I am actually installing this at the moment for a small business. It is very very good and allows for expandability as well as all the features. I would highly reccommend one, much better than anything over USB as you can intergrate with network as desired. Much less hassle!

    Synology 211+

    Hope that helps a future choice

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