RAID 5 configuration

Discussion in 'Mac Pro' started by ghostlight, Feb 6, 2008.

  1. ghostlight macrumors newbie

    Feb 6, 2008
    okay, i have 4 500GB drives equalling 2TB.
    i did a RAID 5 on all 4 drives (at least i think), but now here's what i have.

    one macintosh HD, and one RAID volume. the mac HD seems to have full capacity, but my RAID volume only has 750GB free space. I'm guessing that i shouldn't have that mac HD and that it should have been included in the RAID configuration, but it wasn't. because if all 4 hard drives were RAID configured together, i should have 1TB capacity...

    am i correct? and if so, what do i need to do to get that last hard drive into the configuration?

    thanks everyone!
  2. edesignuk Moderator emeritus


    Mar 25, 2002
    London, England
    If all 4 drives were sitting in RAID5 you'd have 1.5TB (well, less than that after formatting, but anyway...).

    I have no idea how you've come to have what you have :confused:

    Maybe post some screen shots from disk utility for us to see?
  3. tersono macrumors 68000


    Jan 18, 2005
    If you did it in software, you have RAID 0, 1 or 0+1 NOT RAID 5.

    You'd need to have the optional RAID card to enable RAID 5 - and, as the other poster says, you'd get 1.5 TB with 4 drives, or 1TB with 3.
  4. ghostlight thread starter macrumors newbie

    Feb 6, 2008
    here's a screenshot of what i have...:confused:

    Attached Files:

  5. ghostlight thread starter macrumors newbie

    Feb 6, 2008
    i do have the Raid card enabled. it seems i didn't include one of the drives in the configuration? how can i start over and include all 4 drives this time?

    here's what the Raid utility looks like...

    thanks again!

    Attached Files:

  6. mlsiemon macrumors newbie

    Feb 4, 2008
    Looks OK in Raid Utility...

    The 1.19 TB shown for the R0-1 RAID set is what you get formatted for the raw 1.5 TB (500 Gig being used for redundancy/parity from your original 4 x 500 G drives). This is exactly what my RAID is being set up as right now (about 2/3 of the way through the process :) -- what is the convention for an "impatient" smile?)
  7. mlsiemon macrumors newbie

    Feb 4, 2008
    It's two, two, two volumes in one [set]

    Oh, that bit about the 750GB "free space volume"? One of the options when you migrated the original 1 drive to a 4 drive RAID 5 was to use the additional space for a new volume (this is not particularly clear in Raid Utility ...). This gives you a startup volume equivalent in space to your original one drive (but striped over the RAID), plus another (751.33 = 1.19T - 465G...) that you can use for other stuff (in my case, media data that will be backed up separately from the boot partition.) There is really just one RAID set that is divided into two. I don't know if you can "migrate" that back to a single volume (without having to save/restore the data) if that is what you had intended to do.

  8. MrPDaddyHimself macrumors regular


    Jan 8, 2008
    On a different note, I have migrated my drive 3 and 4 into a RAID Set of 0. If I want to combine Drive 1 and 2 making this a RAID 0+1, do I need to delete the RAID 0 set and start over or can I just select my Drive 1 and tell it to combine Drive 2 and the new RAID Set to achieve what I wanted? In other words, will I need to start over or am I still o.k.? Anyone?

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