Create a single disk from multiple externals

Discussion in 'Mac Accessories' started by Wardotron, Sep 23, 2011.

  1. Wardotron macrumors member

    Oct 30, 2008
    Hello all.

    Like most seasoned users, I have a small menagerie of external hard disks of various sizes. Is there a way to reliably turn multiple external drives into one single volume?

    Thanks in advance...
  2. miles01110 macrumors Core


    Jul 24, 2006
    The Ivory Tower (I'm not coming down)
  3. Wardotron thread starter macrumors member

    Oct 30, 2008
    I gather that Disk Utility makes this possible, but is it a reliable solution?
  4. KScottMyers macrumors regular

    Jul 17, 2009
    Orlando, FL
    To use drives of different sizes - this is a good solution. You can mix and match drive sizes and it shows up as one volume - in a easy-to-use redundant solution.

    Starts at $399.
  5. maflynn Moderator


    Staff Member

    May 3, 2009
    I've only seen people post complaints and issues with Drobo so I'm not sure its a good solution. If you're dropping 400 bucks on an enclosure, I'd rather spend it on a NAS enclosure that seems to have a better track record. Synology is very popular here and QNAP is an excellent alternative.
  6. KScottMyers macrumors regular

    Jul 17, 2009
    Orlando, FL
    I've seen some of these comments, but I've been using a Drobo for a while with no issues. There are definitely a few solutions out there.
  7. talmy, Sep 23, 2011
    Last edited: Sep 23, 2011

    talmy macrumors 601


    Oct 26, 2009
    With the keyword "reliable" I'd say "no". RAID won't work with differing drive sizes and while you can do a "concatenated disk set" with Disk Utility if any drive fails you lose everything.

    Most external drives these days are sealed into their cases. If you can remove the drives a Drobo would work, but it is likely too expensive a solution to salvage what are probably a collection of small and fairly worthless (based on 2TB drives <$100 these days) drives.

    Edited to add the "start over" approach. Toss those existing drives. Then you can buy a dual drive housing capable of RAID (if you wish) from OWC for $100, and add two 3TB Hitachi drives from Newegg for $260. That would give 6GB capacity for less cost than the bare Drobo alone. That ought to hold you a while!
  8. Paulywauly macrumors 6502a


    Sep 26, 2009
    Durham, UK
    You can create a software RAID disk in the Disk Utility, but there are some cons to this:

    1. Its software RAID rather than hardware RAID, which isnt as reliable or fast.
    2. The discs need to all be the same size.
    3. While RAID creates redundancy, you're more likely to have problems with the RAID set as a whole as every external drive you add adds to the increased risk of failure.
    4. You havent mentioned backing this large, distributed volume up which is basically just asking for trouble!

    If you dont have the money to go out and buy a dedicated RAID box or Drobo you may be better of just using half the discs for storage, then use the rest of them for automated frequent backups (i recommend Carbon Copy Cloner)
  9. marzer macrumors 65816


    Nov 14, 2009
    I have used the built in software RAID successfully in the past to do just that, consolidate four externals into bigger storage volumes. What I experienced, though, was that for USB drives anything more than 2 in a RAID (either 1 or 0) set was prone to frequent corruption. So I did sets of two which provided enough volumes to have a primary and a backup in case of RAID or disk failure. Of course it takes alot of USB ports to have that all running. After about 6 months running like that, I went with OWC enclosures to reduce power and port needs.

Share This Page