Hardware RAID and OSX/Windows

Discussion in 'Mac Pro' started by tomllama, Mar 10, 2010.

  1. tomllama macrumors regular

    Jan 7, 2007
    I have no experience with hardware RAID, so forgive a probably silly Q:

    Say I want to create a RAID 10 configuration that allows booting to either OSX or Windows using only the 4 internal bays.

    Do the Areca or equivalent cards allow a physical drive to be partitioned and treated as separate 'drives'? Could one take 4 x 2TB drives and partition each as 1 TB for OSX and 1 TB for Windows and then stripe two and then mirror? The result desired would be a RAID stripe of 2 TB that is then mirrored for each OS.


    Does the hardware RAID render the 'normal' differences in format (NTFS/HFS+) of the drives moot and either OS could be used and booted with the same RAID? (because the OS doesn't deal with the disk allocation, the RAID hardware does?)
  2. Dr.Pants macrumors 65816


    Jan 8, 2009
    From what I've read, it is the card that won't allow dual-booting OSX and Windows (Nanofrog wrote something about this), but the specifics escape me at the moment.

    If you have a need for a heavy amount of disc access, maybe you can live with a drive for OSX, a drive for Windows, and then data on the 4-drive array? I know its a PITA to do (six drives require some extra wires and, for the anal retentive like myself, mounts), but for RAID on only one machine using four drives its about the only solution (Unless you want windows or OSX on the array)
  3. nanofrog macrumors G4

    May 6, 2008
    Unfortunately, this is impossible. You either load BIOS or EFI. No card can contain both firmware formats needed to boot.

    In order to have separate bootable arrays, you'd need 2x cards (one EFI, the other BIOS), and separate drives per card.

    Yes. You create the array on the card, then partition via the OS. You also have to format the partitions, so say you have an HSF+ array, it won't be accessible to Windows (natively).

    Sort of. You'd make a single array under the card, then partition it. Then format each partition to the desired file format (i.e. NTFS on one, HSF+ on the other). Then each is ready to hold data for their respective OS's.

    You could run into throughput issues this way as well, as the partition #0 will be the faster tracks, while the 2nd partition will use from the 50% mark on (inner most tracks = slower). This can be dealt with, by either keeping the data less than full, not having the partitions equal size (data still on the 0 - 50% mark of the set), or add drives. It could increase your costs, as I don't know the details of your throughput or capacity requirements.

    But you'd need a separate boot drive per OS or use Boot Camp to share one array with multiple OS's. Personally, I'd recommend separate drives (that way if one of the OS drives goes, the other is still intact, and may assist in troubleshooting/rebuilding). This is especially usefull to gain access to the card, as it uses a web browser to do so (you can also use CLI, but the web method is easier).

    This is one way to do it , and is the most cost effective means to do so.

    I'd recommend it, unless there is a true need for separate bootable arrays, and the funds to do it. The reason is cost, as for 2x bootable arrays, 2x RAID cards would be needed, enough drives for 2x separate sets, and likely external enclosures and the necessary cables (especially using 3.5" drives; 2.5" might be doable internally if the drive count is kept low, and perhaps the optical drive would need to be moved externally).
  4. jrlcopy macrumors 6502


    Jun 20, 2007
    So does this mean that if I was to create a hardware raid of 2 drives using the raid card, but I kept windows / osx / linux on another drive all together, I still couldn't access those 2 drives?

    Is there currently ANY solution that would allow me to setup an internal raid 0 that would be able to be accessed from both a windows / osx / linux boot?
  5. nanofrog macrumors G4

    May 6, 2008
    Generally speaking you can, and there's 2x ways to do it.
    1. Use a file system that all the OS's can access (i.e. FAT32). FAT32 has limitations though, and isn't ideal. But it's doable. You get both read and write access.

    2. Software, such as MacDrive, which allows one OS to access another's filesystem. Now AFAIK, LINUX can't write to HSF+ (read only), but it can with HSF (read + write natively).

    So you could format the partition with HSF, and use software to allow Windows and OS X to use the same partition as well (you'd only need to use MacDrive on the Windows side, as OS X and LINUX can deal with HSF natively).

    Hope this helps. :)
  6. jrlcopy macrumors 6502


    Jun 20, 2007
    Thanks, aside from the file system, If I was to make a raid with the mac raid card, and format it with HFS+ I'd be able to access that RAID in windows?
  7. nanofrog macrumors G4

    May 6, 2008

    The Apple RAID Pro Card:
    1. ONLY supports OS X (you need it to have drivers to support any other OS, and Apple never wrote them, nor will they. EVER).
    2. It's S-L-O-W.
    3. Still has battery issues.
    4. Only a 4 port model.
    5. Expensive

    Add it up, and it's a POS. Seriously.

    Go with Areca, Atto, or Highpoint's RR43xx series, as they're EFI bootable, have drivers that support multiple OS's, are faster, have additional features, and are cheaper for what you get (i.e. there are models that out cost the Apple card, but it will be much faster, have more ports on it, and may even allow you to upgrade the cache capacity via a DIMM slot).

    BTW, if it's OS X and Windows ONLY, you can use HSF+ with Windows so long as you use MacDrive (or a similar bit of software). It's Linux that forces HSF (can't deal with extended journaled last I knew).

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