Two Mirrored External HD's?

Discussion in 'Mac Basics and Help' started by sammyman, Dec 27, 2009.

  1. sammyman macrumors 6502a

    Mar 21, 2005
    My wife is a photographer, and currently all of her pictures reside on an external hard drive. I bought a second hard drive thinking that I could mirror, or setup some kind of raid so there is some redundancy (and some backup!) for her pictures. Can someone tell me how to properly setup the hard drive for her so everything is backed up twice through RAID? Or is there a better way to do this?

    One hard drive is firewire (g-drive), and the new one is a cheap western digital usb hard drive. I don't know if it matters if they are usb & firewire. If it does, maybe I could set up the other drive to make backups daily or something.

  2. sammyman thread starter macrumors 6502a

    Mar 21, 2005
    I figured out how to mirror the hard drives, but now I can't make an image of the existing hard drive (700gb of 1tb used). It gives me all kinds of errors. Input output error, unable to create image error etc.
  3. blodwyn macrumors 65816

    Jul 28, 2004
    Portland, Oregon
    AFAIK you can't create a mirror while preserving the data on one of the drives. Creating the mirror erases both drives, then creates the mirror. To do what you want you would need to be able to copy the 700GB somewhere, create the mirror, and then copy the data back again - a real pain with that much data.

    Your best bet would probably be to create a mirror with two new drives, preferably in a single external enclosure. If you do what you're suggesting with two external drives on 2 different buses, and one of the drives gets disconnected for any reason (hub glitch, cable problem, accidentally unplugged) then your mirror is smashed and you will have to rebuild it. I had this with 2 drives on a USB hub, which turned out to be flaky. After the third time I had rebuilt the mirror I ditched the hub and bought a twin drive external enclosure.
  4. Jaro65 macrumors 68040


    Mar 27, 2009
    Seattle, WA
    I am in a similar situation, in that I also needed to back up my images using some type of redundant solution. After doing some research, I ended up purchasing a Western Digital My Book Studio Edition II drive. This drive's capacity is listed as 2 TBs, but internally it is actually built using two 1 TB drives. The included WD software makes it super easy to enable a Raid 1 drive mirroring, giving you an effective capacity of 1 TB. There are other solutions offering even higher redundancy or capacity (such as Drobo), though these get more expensive.

    Just FYI, here is a link to the WD drive (I actually have 2 of these):

    Good luck!

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