RAID advice for new Mac Pro

Discussion in 'Mac Pro' started by cowm007, Mar 3, 2008.

  1. cowm007 macrumors regular

    Feb 2, 2005
    I just purchased a new Mac Pro to replace my current Windows Desktop. I have 2x500 GB drives in RAID 1 now which I'm looking to migrate to the new Mac. Now, I need to expand my drive capacity so I'm buying two new drives to do a 4 drive RAID array.

    I really wanted to do a RAID 5 set but the Mac Pro RAID card is just too expensive (and it only supports 4x SATA drives) and 3rd party cards have gotten bad review. So instead, I'm looking at doing a RAID 10 set.

    To sort of future proof, I'm want to get 2x750GB drives but I have a couple of questions.

    • First off, if one of the 500GB drives already has data, can I make the RAID array without having to reformat that drive?
    • Second, I've never worked with RAID 0 stripes, so if I make a RAID 10 set (2x500 RAID 1 + 2x750 RAID 1, RAID 0 of both sets), will the max capacity be 1 TB or 1.25 TB?
    • Finally, if later on I replace the 500GB drives with 750GB ones, can I update the set without a reformat?
  2. jb60606 macrumors 6502a

    Jan 27, 2008
    don't know about your other questions, but I believe all drives will be wiped clean when creating a RAID array. Meaning, you'll lose all your data.
  3. Play4keeps macrumors regular

    Apr 20, 2006
  4. hulkss macrumors newbie

    Jan 9, 2008
    How I set-up a four drive disk array

    Here's how I set up 4 750 GB drives using Disk Utility software RAID. OS X runs fast in a striped raid array. The two OS X data storage partitions are mirrored to tolerate a drive failure. Time machine backs up the three OS X partitions to an external 2GB disk array. The Windows partitions are backed up to a 500 GB external drive. This works great for me as I work mainly on the Mac side.

  5. bigbossbmb macrumors 68000


    Jul 1, 2004
    take a look at the new CalDigit RAID Card. It is complete hardware RAID (unlike the Sonnet stuff) and sells for less than the Apple Card. It also supports up to 12 External drives on top of the 4 internal bays.

    Pretty awesome...
  6. cowm007 thread starter macrumors regular

    Feb 2, 2005
    I like this card much better than the Apple RAID card but it's still very expensive at $550. Might as well buy 6 new drives for that price and stick with RAID 0 and RAID 1 arrays.

    It used to be that drives were very costly so it was a good investment to buy a good RAID card. But with sub $100 drives with 500GB capacities, the benefit is starting to diminish. It'd be nice to see these cards keep up with the market.
  7. cowm007 thread starter macrumors regular

    Feb 2, 2005
    I finally got my Mac Pro and I did some minor tests with the RAID features. In the end I decided to go with a 4-drive RAID 10 set and it works very well. I've even tried removing 1 drive from each of the two mirrored sets and OS X handles it well. Plugging the drives back in (after powering down of course) triggers a rebuild and after a couple hours the RAID array is as good as new.

    I like this because I can run the RAID array with 2 drives while I finish building my custom bracket. Then I just add the other 2 drives and OS X handles the rebuilding in the background.

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