Need help getting my RAID5 array to work...

Discussion in 'Mac Basics and Help' started by RedTomato, Jun 27, 2006.

  1. RedTomato macrumors 68040

    RedTomato

    Joined:
    Mar 4, 2005
    Location:
    .. London ..
    #1
    Hello,

    I finally got round to installing and setting up my RAID5 array using a Rocket Raid 2220 card.

    Had 2x300 GB drives, new and empty + 1x 300 GB drive already full of archived data.

    Out of this, the aim is to set up a RAID 5 using all three drives, 900GB raw for 600 GB of redundant storage. My 300GB of archived data is to fill half of this redundant storage.

    Hmm, how to set up the RAID 5 given that the card needs to reformat all three drives to make it work.. ?

    That's where my problems started. Read on to see where i failed miserably.

    Here's what I did:

    1. Connected the new 2x300 GB drives to the card, initalised them, and set up a small JBOD of 300GB.

    2. The new JBOD appeared in Finder (OS 10.3.9) as an unformatted 300GB drive. Used Disk Utitlity to format it in HFS+

    3. Connected the (full) legacy 300GB drive to the computer, and transferred the 300GB over to the JBOD,

    4. Moved the legacy 300GB drive to the RAID card, and initialised (erased) it.

    5. Used the card's ' Online Migrate / Change RAID level' to change the 300GB JBOD into a new RAID5 array using all three drives, with 600GB of redundant storage (half this space will be taken by the migrated data (300GB) from the JBOD)

    6. After 13 hours, the process is finally finished.

    Hurry! My precious 300GB of archives is still there!

    Gadzooks! I can't access the extra 300 GB of redundant storage :(

    Finder shows a mounted partion of 300GB, full of my data, which I assume is now sitting on a RAID 5 array, but where is the other 300GB of space?

    Rebooting and restarting Disk Utility shows a (virtual) drive of 600 GB (actually 558.6GB but lets not quibble), with a single partition of 300 GB.

    It seems OSX can't access the empty space or add an extra partion without erasing the entire virtual drive even tho the space is empty :(

    Now I'm on the short bus up the brown creek without a paddle :(

    What did I do wrong? How can I access my full 600 GB of RAID and still keep my 300 GB of archives?

    Any ideas would be appreciated (Especially from CanadaRAM )

    .. RedTomato ..
     
  2. RedTomato thread starter macrumors 68040

    RedTomato

    Joined:
    Mar 4, 2005
    Location:
    .. London ..
    #2
    Been thinking about this.

    Part of the plan for future expansion was to buy extra 300 GB disks as the need arose and add them onto the RAID5 array.

    I'd be willing to buy a new one now (tho I'd rather not just now) to copy over the 300 GB of archive data, and then re-initalise the array.

    Problem is supposing I do all that, and erase the new disk, I'm left with

    1x 600GB partion on a 600GB virtual HD on RAID5 storage on 3x300 HD

    + 1x blank 300GB disk.

    If I add the new disk to the RAID5 array, to create a 900GB virtual disk, I'm left with exactly the same problem as before, of not being able to access the new storage space, only the previously existing 600GB partition.

    I'm stuck here. I must be missing something simple otherwise I've wasted my money buying this expensive equipment.

    I hope I'm clear enough - this is my first time setting up a RAID5 array.
     
  3. CanadaRAM macrumors G5

    CanadaRAM

    Joined:
    Oct 11, 2004
    Location:
    On the Left Coast - Victoria BC Canada
    #3
    Ummm... I dunno.

    My initial reaction is -- borrow a 300 GB, back off the data, do the whole format and setup Raid5, and put the data back on.

    I just don't know how to change the intrinsic properties of a RAID while preserving data on those same disks.
     
  4. RedTomato thread starter macrumors 68040

    RedTomato

    Joined:
    Mar 4, 2005
    Location:
    .. London ..
    #4
    mmm, getting another 300GB disk isn't a big problem, but future expansion will be.

    My real problem isn't changing "the intrinsic properties of a RAID while preserving data on those same disks." - the RocketRaid 2220 deals with that quite well.

    The problem is as I expand the RAID array and it increases the size of the virtual disk it presents to the Finder, how can I actually access and use that increased disk space?

    http://www.coriolis-systems.com/iPartition.php might be a solution. That would help me add extra partitions / expand partitions on the virtual disk that is presented to the Finder.

    Wonder how OS X Server deals with partition management on the changing sizes of virtual disks presented to it by Xserve Raid, where adding / subtracting disks could be a common occurence?
     
  5. superbovine macrumors 68030

    superbovine

    Joined:
    Nov 7, 2003
    #5
    when you say JBOD using 2 x 300 gb drives you mean it was in a RAID 1. A JBOD can be a RAID 1, but normally a JBOD would be 600 gb in your case. When you "migrated" to a raid 5 you only see the extra 300 you see it separately. first, off you should understand that I have never used you card before, but about 90% of the issue I deal with everyday (all day) are RAID and JBOD related. My guess is you expanded capacity (which your card supports; i looked) instead of making it a RAID 5. A lot of different RAID controllers have this feature, and I get a lot of calls with the same confusion. You probably need to read up on your card, because I am very sure your issue with understand how the card works vs what you think you did.
     
  6. Nermal Moderator

    Nermal

    Staff Member

    Joined:
    Dec 7, 2002
    Location:
    New Zealand
    #6
    Take a look at diskutil's resizeVolume feature. I can't go into any further detail as I've never used it ("man diskutil resizeVolume" maybe? I'm on Windows at the moment so can't check).
     
  7. RedTomato thread starter macrumors 68040

    RedTomato

    Joined:
    Mar 4, 2005
    Location:
    .. London ..
    #7
    Hi superbovine,

    Thanks for your help,

    I'm quite clear I made a JBOD in the first step, I selected that option from the card's web configuration - yes I only used 300GB out of the total of 600 GB available for the JBOD.

    Why? Cos I thought it might take less time to migrate to a RAID 5 than if I made a full 600GB JBOD. Not sure if that was true or not.

    I'm also clear I definitely migrated it to a full RAID 5 - the card supports changing RAID levels on-the-fly. It now uses all three disks to full capacity for a total of 600GB of RAID level 5 storage.

    Superbovine, with your experience, can you tell me, if you increase the size of a card-managed array, how do you give OSX access to the new space? Does it just 'pop up' in the Finder?

    Example: 100GB array, (spread over a couple of disks, doesn't matter if it's JBOD or RAIDx), is presented by the card to OS X as a single 100GB disk. It's partioned into a single 100 GB volume.

    Now add an extra 50 GB physical disk to the card, and expand the array on the fly. Now the card is presenting a 150GB disk to the OS.

    OSX believes it's seeing a single 150 GB disk, but it still has a single 100GB volume on it. It can't access the extra 50 GB without making a new partition. (or expanding the single partition.) Unfortunately, OSX can't expand partition or add new ones to a disk without reformatting the whole disk.

    This is a big difference between OS X and Windows. In Windows, I was used to slinging around and resizing partitions every week. Here I can't do it :(

    How do you get around this issue without backing up, erasing and restarting the whole array (JBOD or RAIDx) every time you want to add capacity to it?
     
  8. RedTomato thread starter macrumors 68040

    RedTomato

    Joined:
    Mar 4, 2005
    Location:
    .. London ..
    #8
    To Nermal, thanks, I had a look at diskutil - there is no resizeVolume of any sort. I think that's only on Windows / unix filesystems. OS X uses a non-unix filesystem even tho it's based on unix.

    man diskutil on OS X lists the usual options - mount, unmount, partion, erase, createraid, destroyraid, verify etc etc but no non-destructive volume management.
     
  9. Nermal Moderator

    Nermal

    Staff Member

    Joined:
    Dec 7, 2002
    Location:
    New Zealand
    #9
    Oh sorry, I didn't notice that you're on 10.3.
     
  10. RedTomato thread starter macrumors 68040

    RedTomato

    Joined:
    Mar 4, 2005
    Location:
    .. London ..
    #10
    Yes, I'm runnnin 10.3.9

    If 10.4 has volume resize then that'd be a very very good reason to upgrade :)

    EDIT: googled diskutil volumeResize - while it is included in PPC OS 10.4.6+ it actually *only works* on Intel Mac drives - they use a slightly different drive mapping system to enable Boot Camp to work.

    Damn. I'm on a PPC mac.

    Am on the point of buying iPartition in the hope that it will sort out adding partitions.
     
  11. superbovine macrumors 68030

    superbovine

    Joined:
    Nov 7, 2003
    #11
    Sorry I didn't your post carefully enough. I understand what you did now. (i hope).

    It seems that it is doing exactly what it is suppose to do. Your container size is static. you need to use some type of software to make your volume dynamic. that is how most RAID controllers worked. remember OS X doesn't have any knowledge of the drives unless you use specialized software to access the controller. however, all OS X knows that it has a logical drive that is this much and it cannot expand it. Now, the controller can handle adding another drive and it just tells the operating system that there is a new space out there, but it cannot add it to the existing container. At this point it would be an operating system operation because altering the HFS+ involves the OS writing to the hd. Your only hope to resize it with software as well like the other people have said before.

    whenever an enterprise customer ask me how to migrate their data like that or add to their raid 5. i always recommend image your logical drive and restart your array from scratch. the only time i give the ok is when it is a raid 0 (single drive) -> raid 1 or a 3 hdd of the same size, and two are in a mirror and it is going to a raid 5.


    http://www.macgeekery.com/tips/cli/nondestructively_resizing_volumes
    http://www.subrosasoft.com/OSXSoftware/index.php?main_page=index&cPath=32
     
  12. RedTomato thread starter macrumors 68040

    RedTomato

    Joined:
    Mar 4, 2005
    Location:
    .. London ..
    #12
    Thanks for your helpful replies.

    I finally solved it after much research.

    I now have full access to all 600 GB and can expand / add new partitions whenever I add extra drives to the RAID5 array in future.

    iPartition, VolumeWorks and Drive Genius can all change volume size, but they don't shout about it.

    iPartition - have to use the oddly named 'Expand Partition Map' function - this was described as:

    It seems to also work in the case of a virtual drive that has been expanded by an array manager. Downloaded a demo from their website and it seemed to work perfectly. (demo doesnt let you commit actions to disk tho)

    VolumeWorks from SubRosa has the same function, called 'Reset Partition Map', described as

    Drive Genius from prosofteng includes VolumeWorks as part of it, but has a lot more disk utilities, such as benchtesting, sector editing, imaging, stress testing etc, so in the end I went for it and used it to expand my partition.

    iPartition is GB£25, and has the most intuitive visual interface, and is suitable for non geeks who want to do basic partition operations.

    VolumeWorks is US$50, does not show partition maps so clearly (but is perfectly useable), and lacks some of the tools of iPartition.

    Drive Genius is US$100, includes VolumeWorks and many many more drive tools as mentioned above, more than the other two, all wrapped behind a visual interface. This the one I got.

    Free option - it MIGHT be possible to do the same using pdisk (and possibly diskutil) from the terminal window. This requires calculating and typing in partition block start and end numbers, something I haven't done for nearly 10 years. If you choose this rather insane route, recommend updating your OS to 10.4 as Apple has done a lot of work on pdisk lately. OS 10.3.9's pdisk was last revised in 1997 (!)

    Hint - while using the above programes stick to expanding/ resetting partition maps, or basic operations like deleting / adding new partitions.

    With valuable data, don't try anything involving moving partitions around or other exotic operations.

    Almost all the failures and lost data while using the above programes have been due to power failures, OS crashes, and other problems while carrying out partition moving or other slow/ complex operations on your precious data.

    Hope this helps other people who have the same RAID issues. And there's a lot of them - I've seen this question asked all over the the net, without any single helpful answer up to now.

    cheers

    ..RedTomato..
     

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