Areca RAID + Expanding Volume

Discussion in 'Mac Pro' started by monksealpup, Nov 9, 2009.

  1. monksealpup macrumors regular

    Joined:
    Jun 12, 2009
    Location:
    Honolulu, HI, USA
    #1
    I am wondering if anyone has experience with the following situation:


    I have an Areca RAID card (1680) with 4 1TB drives in a RAID 5 setup. I am wondering if it's possible/easy to add another 4 drives through an external enclosure and expand my setup to an 8-drive RAID 5 setup. The extension of the RAID array is easy, and I see how to do that through the RAID card, the question I have is once I do that, can I just expand the boot partition in disk utility to fill up the 7 TB array, or will I have to reformat to use the additional 4 TB?

    If anyone has any experience with this, I would very much appreciate hearing about your experience.

    Thanks a lot!
     
  2. nanofrog macrumors G4

    Joined:
    May 6, 2008
    #2
    As you hoped, online expansion is easy. Add them to the card, and go into the Web util. Then select Expand Raid Set, select (drives), and hit submit.

    Once it's done, you can resize the partition (under Modify Raid Set), so long as it's larger than the data contained. No data loss. Also easy to do. :D

    Even so, it's best to make sure you have a fresh backup before proceeding, as there is the occasion things can go wrong.
     
  3. monksealpup thread starter macrumors regular

    Joined:
    Jun 12, 2009
    Location:
    Honolulu, HI, USA
    #3

    All of that is through the RAID controller. Will Disk Utility allow me to change the partition size (bootable partition) to fill the new space without losing any data? Presumably I have to boot from another disk to do this.

    Thanks for all your help so far!
     
  4. nanofrog macrumors G4

    Joined:
    May 6, 2008
    #4
    The disks are attached to the RAID card, so you have to use the Web Util or the card's firmware.

    If you don't there's a good chance that the OS util operates in a manner that's not compatible with the card, and has too much potential not only to wipe the data, but even blow the array (assuming there's no safety feature to prevent it with OS X).

    I never tried using the OS tools to make changes (any OS), as it was too risky. So I stuck with the Web Util or Firmware to access the array/s, no matter the OS involved.
     
  5. monksealpup thread starter macrumors regular

    Joined:
    Jun 12, 2009
    Location:
    Honolulu, HI, USA
    #5
    I understand what you're talking about, but that just expands the array. The partition doesn't change sizes until you open disk utility and do it, to my knowledge. For example, I have a 3 TB array now, which is in 1 partition of 3 TB. If I expand the volume, it will read a 3 TB partition on a 7 TB volume (i.e. it thinks the volume's max capacity increased between boots). My question is, can I just resize the partition in disk utility to 7 TB without destroying the data on it? I seem to recall that boot camp does this (allows you to dynamically shrink the HFS+ partition to make room for a FAT32/NTFS partition, and to undo that process), so I am wondering if it will work for simply expanding the boot partition.
     
  6. nanofrog macrumors G4

    Joined:
    May 6, 2008
    #6
    I tried to explain how to set the partition values in post 2, but left out too much, as it varies (a. card models, b. location of original setup).

    If you set up the array as a single partition on the card, then want to make a partition, you do go ahead and use Disk Util.

    Some of Areca's cards won't let you make the partitions on the card (it only makes 1 partition per set). So you have to set the partition via Disk Util in OS X.

    IIRC, you can also do it from the Firmware (usually how I do the initial config).

    At this point, I'll presume the array = single partition. Go ahead and use Disk Util, as you won't end up with unused (and inaccessible) capacity.

    Sorry about the confusion. Hopefully, this will clear things up.
     
  7. monksealpup thread starter macrumors regular

    Joined:
    Jun 12, 2009
    Location:
    Honolulu, HI, USA
    #7
    Awesome; everything is cleared up. Thanks again for all the help!
     
  8. nanofrog macrumors G4

    Joined:
    May 6, 2008
    #8
    :cool: NP. :)

    Glad you've got it sorted, as it's not necessarily the easiest thing to accomplish with an unfamiliar RAID controller. I've never had one from different manufacturers work exactly the same. :rolleyes: ;)
     

Share This Page