PCI Hard Drives

Discussion in 'Mac Pro' started by haravikk, May 14, 2010.

  1. haravikk macrumors 65816

    May 1, 2005
    Well, something I've been having trouble with on and off has been the fact that I can't boot into Windows as all four of my internal drives are striped in a software RAID. Hardware RAID cards have been more trouble than they're worth, but I've noticed it's now possible to buy solid state drives attached to a PCIe card for additional internal expansion.

    I'm wondering if anyone has tried any of these in their Mac Pro, and if so is it bootable for OS X and Windows? I was thinking it might make sense to get a decent sized one, partition it, and move both OS X and Windows to it, then use my existing RAID array for only the really huge files that I set it up for.
  2. nanofrog macrumors G4

    May 6, 2008
    Unfortunately, when you create a software RAID under OS X, Disk Utility makes a change in the system's firmware, which is what prevents a single separate disk from working (you can't use BC either, as the GPT -GUID Partition Table system used in OS X is incompatible with Windows).

    So ultimately, once you make a software RAID under OS X, Windows can't be run off of the logic board's SATA controller. :(

    There are ways around this, but they all involve a card of some kind, which means additional funds. Fortunately, if you're willing to use a mechanical drive, it's not nearly as expensive as an SSD, let alone a PCIe Flash drive.

    Options (works with both HDD or SSD):
    1. Use a SATA/eSATA card to run a Windows disk. It must have a boot ROM containing BIOS to do this however. Fortunately, most do. Any PC card will work if you've no intention of running it under OS X. There are also options that can run under OS X via drivers as well as boot Windows (SIL3132 based - example).

    This is the cheapest option. But the least expensive cards aren't 6.0Gb/s capable (the SIL3132 = 3.0Gb/s, and isn't the best suited for SSD's, but is fine with mechanical). Here's a 6.0Gb/s card that would work as well (again, it boots Windows, but only works under OS X via drivers).

    2. Place the RAID under a hardware RAID card (it will work with proper planning, as most problems are a result of incompatible hardware, namely drives). There are additional benefits, such as no load on the system resources, ability to move it from system to system, and performance increases. Then there's other levels if the card is capable.

    Up to you.

    See above. ;)

    I can provide more information if you do decide to consider this route, but keep in mind, RAID cards are picky with drives (has to do with recovery timings in the firmware, which are different with consumer models). Enterprise drives are typically 0,7, while consumer models are 0,0 (seconds; read, write). Then there's the additional sensors and improved specifications, such as higher MTBF ratings and UBE values, which translate into drives meant for high wear environments (Mean Time Between Failure and Unrecoverable Bit Error respecitively).

    They are more expensive, but are worth it. RAID can also work with SSD's, and the performance can exceed what's possible in the built-in controller in the ICH9 in the chipset (throughput limit of ~660MB/s, no matter the drive count/type), and a fast SSD RAID can exceed that with as few as 3 disks (known as throttling).

    I'm not aware of one that can operate under both OS's.

    Fusion I/O has indicated that they will support OS X in past news briefings, but so far, only Windows and Linux support is available (OS X support is presumably still pending, boot or otherwise). Steve Wozniak is involved in the company, and is in the hardware development side as I understand it.

    Unfortunately, I'd have thought OS X support would be out by now. :(

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