Old MSI NEO fis2r with promise raid.

Discussion in 'MSI' started by Menthol, Oct 5, 2007.

  1. Menthol

    Menthol Guest

    I have been trying to figure this out.....

    I want to have a raid0 i.e. striping across 4 sata disks 3x250gb and
    1x120gb.

    I also want my IDE CD-ROM to work.

    I can't seem to find the right combo in the Bios on how to set it up
    and when I get the raid setup screen it only shows 2 drives not 4.

    Anyone?

    Thanks,
    M
     
    Menthol, Oct 5, 2007
    #1
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  2. Menthol

    Glasspider Guest

    All your drives have to match, preferably all the same exact model. The
    speeds of modern drives have made RAID setups much less useful than they
    used to be. They're rarely worth the trouble and the extra hard drive
    space is always useful.
     
    Glasspider, Oct 5, 2007
    #2
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  3. Menthol

    Menthol Guest

    They have to match in order for me to stripe them? Having
    250+250+250+120 and making a 870gb disk out of them?

    I could use software to join them as dynamic disks under windows but I
    wanted to do that with the existing promise raid on the MSI board.

    I know that if I made a raid5 out of them the 250 disks would only
    really work as 120's
    But a stripe?


    -M
     
    Menthol, Oct 5, 2007
    #3
  4. Menthol

    Glasspider Guest

    Your problem may be a mix of drive speeds.

    However, unless you've got a 300G file you need to store, you'd be
    better off with multiple drives with multiple drive letters. A stripe of
    four drives means a 4x greater chance of complete failure. As individual
    drives you have a normal chance of only a partial failure.

    'pider
     
    Glasspider, Oct 10, 2007
    #4
  5. Menthol

    Paul Guest

    Your board has two separate RAID controllers, each with limitations.
    (My board has the same chips for this, so I've done some research on
    the chips in the past. The following two links, are the RAID manuals
    for my board.)

    http://support.asus.com/technicaldocuments/PDC20378.pdf
    http://support.asus.com/technicaldocuments/ICH5R.pdf

    The Promise PDC20378 is connected to the PCI bus. Theoretical bandwidth
    is 133MB/sec. Practical speed is a bit less than that, maybe 120MB/sec.
    That limitation really makes the potential configurations of the
    connectors on the chip, academic. If you put two SATA drives on
    there, run them RAID0, then you should see your 120MB/sec. Even if
    other interesting modes are available on the chip, you cannot go
    faster than about 120MB/sec anyway.

    In an ironic twist, the ICH5R is the other way around. The hub bus,
    between Northbridge and Southbridge, is capable of 266MB/sec. The
    storage controllers inside the Southbridge, are bridged to the hub
    bus, and are not limited by PCI. But for some reason, the RAID
    feature only works with the SATA ports.

    In practical terms, this means you get two, independent, dual SATA
    drive RAID 0 arrays. If you could find some third party software to do
    a RAID 0 using the resulting RAID arrays (i.e. RAID made from two
    RAIDs), then you might see more bandwidth. But the third party
    software could cost some money, if it even exists.

    Buying another PCI controller is not going to help, because the
    PCI bus limit will exist for that card too. (And that is where
    a new motherboard with multiple PCI Express connectors, would
    help. PCI Express supports high bandwidths.)

    As for the storage capacity, if you did a RAID0 with 250+120, the
    setup will use 120+120 and the remaining 130 will be inaccessible.

    The latest motherboards, that have more SATA connectors, do support
    what you want to do. I don't have any performance figures for you,
    but I believe it is possible to do a four drive RAID0 on the
    boards. The latest Intel Southbridges have six SATA ports, but
    the ports are staged on two controllers. One controller has
    four drives, the other controller has two drives. Only the four
    drive controller is bootable. It is the four drive controller
    which would be the candidate for running a four drive RAID0.

    Nvidia chipsets also are supposed to have flexible SATA configurations.
    The Mediashield Users Manual, from the Nvidia site, suggests that
    all ports which support RAID, could be used in a RAID0 (manual says up
    to eight drives, if there are eight SATA connectors on the board).
    I'd want to see a benchmark, to see whether such a configuration scales
    properly or not. It should, since the bus between Northbridge and
    Southbridge is not likely to be a bottleneck.

    It is not the answer you wanted, but at least you should be able
    to make a nice two drive array on the ICH5R. If you want to use the
    Promise for a second array, I'd pick up another 250GB drive, so you
    can do 250+250 and not lose anything in capacity terms.

    I'm still using a single drive on my motherboard :)

    Finally, as a teaser, there is another way to do RAID. Tomshardware
    had an article a while back, where they did a hack on Windows,
    and Windows can do RAID5 in software. That means your four drives
    use ordinary drivers and not RAID drivers, and then Windows does
    RAID5 on top of that. The drives don't even have to be on the same
    chip. The only reason I did not mention this earlier, is such a
    configuration would not be speedy (XOR parity is done in software).
    And before you tried it, I'd still want to dump the 120GB and buy
    another 250GB, so they match. So this is as close as I can get, to
    building a four drive array with your hardware.

    http://www.tomshardware.com/2004/11/19/using_windowsxp_to_make_raid_5_happen/page2.html

    Paul
     
    Paul, Oct 10, 2007
    #5
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