Is this RAID + Time Machine scenario possible?

Discussion in 'Mac Accessories' started by jamisonbaines, Aug 18, 2013.

  1. jamisonbaines macrumors regular

    Dec 14, 2007
    I don't know much about RAID boxes or NAS options. I'm interested in adding a 4 bay thunderbolt raid to my setup. I would like to configure this in a specific way:

    2 drives (say a pair of 2TB) 1 with each other for media and files.
    2 drives (pair of 4TB) 1 with each other being used for Time Machine backups.

    ^ is this possible? It's similar to how I understand RAID10 except I want the drives to show up as 2 separate pairs.

    ..hold on, I'm not done yet.
    I'd like it to be a hardware RAID capable of rebuilding itself and I would like to be able to have extra duplicates of my Time Machine drive. For example pull one of the mirrored drives from my time machine set, store it off site and slide in a new drive and have it (the raid box) build the mirrored drive.
    So in the ideal scenario I have my media drive(s) and a few laptops being backed up to the time machine drive(s). With a (or multiple) duplicate time machine drives stored off site.

    As an extension to this, when I want to update the offsite duplicate to the current state is there a plausible way to simply append the new/modified files to the old backup or would the backup be doomed to be fully rewritten each time?

    I'd be willing to go so far as building a headless PC strictly for this use, though maybe that would scratch the possibility of thunderbolt connectivity?! Appreciate any info or suggestions.
  2. iamgalactic macrumors regular

    Apr 21, 2010
    i'm in a similar boat...

    if you're time machining with 2 drives in raid 1 you may be better off having your data on the 2x2tb drives in RAID0 for speed. yes, if there's failure you loose all your data, but you'll have it backed up and with redundancy on the other pair...

    i'm looking at a similar setup with 2 lacie 2bigs - and can't decide what to do. RAID10 is one option i'm considering due to 4x read speed. but i've got a separate USB3 drive for time machine anyway - which is making me consider going for the full 4 drives in RAID0 for 4x write speed!

    as far as i know, all the things that you're looking for are possible with software RAID on OSX, i.e. your offsite backups and rebuilds - although rebuilds can take quite a long time (depending on size of disks and number of files) so this may not be best way to keep your backups.

    how about, just as an idea, 4x2tb disks in RAID10 (giving you redundancy) and then 2xUSB3 drives for time machine backups (1 onsite, 1 offsite)?
  3. waw74 macrumors 68030

    May 27, 2008
    you're better off having 2 separate time machine drives.
    that way if one backup corrupts itself you won't just have a second copy of a corrupted image.

    sparse bundles (what time machine uses) can be a bit finicky, i've had them corrupt themselves.

    you could have 3 drives in rotation. 2 local and online and then a third off site, every so often you could bring the third drive back and swap for one of the 2 locals.
    OS X should take care of getting the new drive back up to being current. it will (probably) be missing the incremental hourly backups from the time that it was away. but it should have current and incrementals for the time it was online.

    not sure why you want the time machine drives to be 4TB, if you're planning on using them to back up the 2TB of media, I wouldn't.
    You'll be better off with a straight copy of the files. (corruption issues, and much easier to access the backups if it's just a regular file)

    if you're comfortable with the command line look at rsync for keeping the main and backup together.
    It will compare 2 locations and only copy the files needed to make the backup match the master. (tons of other options also)

    if your mac supports USB3, that is a viable (and probably cheaper) option to thunderbolt.
    unless you have a SSD in your mac, USB3 is faster than your internal drive.

    even USB2 is about 4-5 times faster than straight blu-ray rips, which is probably the highest bandwidth media files that most home users are currently using.
  4. ColdCase macrumors 68030

    Feb 10, 2008
    Perhaps a mis-type, A SSD in an external USB3 drive may be faster than an internal rotary, but an external USB3 rotational would not be faster than an internal rotary.

    Agree that USB3 may be a viable option.

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