Setting up raid with two external drives

Discussion in 'Mac Accessories' started by sinitry23, Nov 19, 2013.

  1. sinitry23 macrumors member

    Aug 30, 2009
    I would like some help on understanding the raid setup from OSX disk utilities.

    Currently I have two WD 8TB My Book Thunderbolt Duo Drives. Each drive will be configured to raid 0 for faster performance. I would like a redundancy backup of the drive. Should I configure raid 1 on both drives through OSX disk utilities?

    -If I configure raid 1 on the external drives and removed one, will I lose the raid configuration?

    -Can I unplug one of the drives and use it on a different computer?
  2. Giuly macrumors 68040


    Setup each of them as RAID1, then you can use them on other computers.

    If you'd to then setups those two RAID1s in RAID0, you'd have twice the speed but you only use them in conjunction on a single Mac.
  3. mfram macrumors 65816

    Jan 23, 2010
    San Diego, CA USA
    Repeat after me: RAID is NOT BACKUP!

    Say it again...


    RAID will help if one of the drives fails. But does nothing to help if you either:

    1. Delete a file you didn't want to delete. Accidentally or otherwise.
    2. Modify a file in a way you regret later.

    That's what backups are for. In most cases, backups are what you want, not RAID. It turns out that Backups also help in cases where a drive fails. Unless you really need 24/7 uptime, I wouldn't worry about RAID and stick with doing backups.
  4. iamgalactic, Nov 20, 2013
    Last edited: Nov 20, 2013

    iamgalactic macrumors regular

    Apr 21, 2010
    but the OP didn't say he wanted RAID 1 for bacukup

    in fact he specifically said for redundancy

    PS - totally agree with you, too many think RAID 1 IS backup ;)
  5. iamgalactic macrumors regular

    Apr 21, 2010
    I have a similar setup with 2xLaCie 2Bigs - running all 4 drives as a stripped RAID 0 for performance.

    What you seem to be suggesting is RAID10. I tried that, but didn't like the speed hit.

    However, I'm not sure that is what you're suggesting as you say "each drive raid 0" then ask if "you should do raid 1 on both drives".

    Depends on what you're needs are!

    You can RAID 1 both drives and then RAID 0 the mirrors or RAID 0 and then RAID 1 the stripes (or just all 4 drives in RAID 0)

    Either way, I don't think you'll be able to plug one of the DUOs into another machine and get the data. Maybe - why not just try it?
  6. sinitry23 thread starter macrumors member

    Aug 30, 2009

    Thanks for your reply. Yes what I'm describing may be for a RAID 10 setup. However, I do want the speeds of a RAID 0 setup. Would it make sense to have one of my external drives setup as RAID 0 and use a software like carbon copy to sync all the data to the second external?

    Can time machine do a backup to what I am describing? I would like a copy of drive 1 to drive 2.
  7. iamgalactic macrumors regular

    Apr 21, 2010
    yes, timemachine can. it depends on what you need. redundancy vs backup.

    RAID 10 will give you reduncancy. if one drive fails in either DUO then your data will be safe. you will have 8tb of storage available from the 16tb total due to the mirror. it will also give you approx 2x write and 4x read

    setup like this

    you can setup one DUO in raid 0 and then the other DUO as raid 1 and use the raid 1 drive for time machine. this will give you 2x r/w on the raid 0 DUO
    time machine can include both your internal drive and your raid 0

    in my 4 drive raid 0 setup i use an additonal usb3 drive as a time machine backup
  8. opinio macrumors 65816

    Mar 23, 2013
    This has been said so many times and it is wrong. Assuming you are talking about RAID 1, yes it is a backup. By english definition is it. A single drive is backup.


    Sorry to be curt, but I have heard this so many times. RAID 0 is excellent and can be part of any backup strategy using CCC, TM, SuperDuper! etc. So can RAID 1. I use RAID 0 arrays in a lot of my backups because I need 8TB plus and also need speed to move TBs each day. I need a solid 200MB/s plus writing and cannot achieve that through standard HDD drives unless I run them in RAID 0.

    So yes, RAID 0, 1 etc is a backup but you need to include those drives/arrays within a broader strategy involving multiple or time-stored backups.
  9. rayward macrumors 68000

    Mar 13, 2007
    Houston, TX

    Apologies if this is a stupid question:

    If I am using an external HDD solely for Time Machine backups, should I use RAID 0?

    Given that it is already a mirror, it seems to me that it's better use of disk space to format the external TM drive to RAID 0 as all the other RAID formats will be duplicating a duplicate. Correct?


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