mirroring and windows server 2008 64 bit

Discussion in 'Windows 64bit' started by Jerry Hoffmeister, Nov 17, 2008.

  1. I have a 64 bit windows 2008 server and want to setup mirroring and have
    several questions. I currently have 1 500gb disk. Obviously I need to get

    1) I've read about how to setup the mirroring and found it mentioned several
    times that the 32 bit os will only boot from a MBR disk and the 64 bit os
    will only boot from a GPT disk. I'm running 64 bit server 2008 and as best
    I can tell, have a MBR disk, not a GPT disk. So are the articles I've read

    2) Looks like all I have to do is add a second disk, using disk mgmt,
    convert the original disk to dynamic then do add mirror...

    3) I assume I need the same size or bigger disk - is it best if it's the
    same model?

    4) My current disk is SATA - I assume that's fine? Also, it's a domain
    controller and is running Exchange 2007.

    Thanks a lot,
    Jerry Hoffmeister, Nov 17, 2008
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  2. You're reading material that is talking about the _other_ 64-bit
    architecture, IA64, used by Intel's Itanium chips. Those do only boot from
    GPT disks, but you're unlikely to ever see an IA64 machine (unless you
    work in a high-performance computing or mainframe-style environment).
    That's the basics for software mirroring, yes. This does impose some
    overhead on the CPU and disk I/O channels. It's also worth noting that
    most disk management utilities (eg partitioning tools and the like) won't
    touch dynamic disks.

    The other option is a hardware RAID controller to do the work - these do
    the work "behind the scenes" as far as the OS is concerned, presenting the
    array drives to the OS as a single logical drive.
    For software mirroring done by Windows, the only requirement is that there
    be enough space on the additional disks for each volume (partition) that
    you want to mirror.

    For hardware mirroring, identical drives are usually recommended.
    Steve Foster [SBS MVP], Nov 17, 2008
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  3. Let me add to Steve's excellent and accurate answer with a caveat. Using
    software mirroring for the boot disk is, certainly, technically possible,
    but it does have some issues, especially around disaster recovery. For a
    real server, I would strongly suggest hardware RAID instead. There are
    excellent, inexpensive, RAID controllers that will give you a better
    disaster recovery scenario than software mirroring. And not require you to
    convert your disks to dynamic.
    Charlie Russel - MVP, Nov 17, 2008
  4. Thank you! Off to buy a second disk :)

    Jerry Hoffmeister, Nov 18, 2008
  5. so the whole point of doing this is for disaster recovery (loss of one of
    the disks) - can you either explain the issues or point me to where I can
    read about it on the web?

    And if I were to buy a hardware raid controller (I assume I can buy a card
    that I then plug my SATA drives into?) will I need to rebuild the server or
    can I start with the currently running drive I have?

    And is there an issue with converting to dynamic disks?

    Jerry Hoffmeister, Nov 18, 2008
  6. and hopefully one last question - any recommendations for an expensive RAID
    controller that supports server 2008? I see a bunch that support 2003 -
    will they work?
    Jerry Hoffmeister, Nov 18, 2008
  7. DR issues:
    * Most DR disk recovery tools don't understand or support dynamic disks.
    * Depending on which half of the software mirror fails, you can be
    unable to boot unless you've created a boot floppy with appropriate boot.ini
    *. No hot swap support, so no way to recover on the fly

    There are some other things that make me dislike dynamic disks, and I always
    dislike any solution that makes my OS do the work in preference to
    offloading it to a specialized processor. Less of an issue for mirroring,
    but a serious issue for RAID-5.
    Charlie Russel - MVP, Nov 18, 2008
  8. I'm guessing you meant "inexpensive"?

    I've heard a lot of good things about 3ware controllers. I've had personal
    good luck with Highpoint, but I've heard some horror stories from others.
    LSI has a good reputation, but tends to be a bit pricier. Built in Promise
    controllers are junk, and I wouldn't use them under any circumstances, but
    their standalone are reputed to be better. Doesn't matter, given my
    experience with their built in ones, they'll never get my money.

    As for supporting Server 2k8? Check the company's web site. If there are
    drivers, you're good. Or the drivers may be built in - but then they should
    have a clear statement of support.
    Charlie Russel - MVP, Nov 18, 2008
  9. Thanks a lot for your help and of course a couple more questions...

    First, should I be able to implement either software or hardware RAID
    without reinstalling the OS? Pretty sure the answer is yes for software but
    for hardware, maybe not? It's a Dell box so I asked their support folks and
    they said I'd have to reinstall which kinda surprises me.

    Turns out I think my motherboard has a builtin RAID controller - an Intel
    ICH9R SATA storage controller but it's just not enabled in the BIOS. I have
    two hosts that are the same - one running 64 bit server 2008 and the other
    Vista 64. I tried just enabling the RAID controller on the Vista 64 box and
    when I rebooted, it blue screened and rebooted... I'm sure I have to do
    some configuring, etc but should I be able to eventually configure RAID 1
    without reinstalling?

    Thanks again,
    Jerry Hoffmeister, Nov 19, 2008
  10. 1) Depends on the RAID controller and implementation. Most will accept an
    existing disk as a master and build the mirror off of it. Some won't. If
    Dell says theirs won't, then I'd believe Dell. But then, I never buy Dell...

    2.) I don't know the capabilities of the Intel ICH RAID controller. But if
    you're trying to boot off it, you'll need to get the drivers on the OS
    before you can make it a RAID controller and boot off it.
    Charlie Russel - MVP, Nov 19, 2008
  11. That makes sense... I got a pretty good response from someon on the dell


    and at least in theory, according to the Dell docs (and the Intel website) I
    should be able to do it. The person replying in the forum has significantly
    better English language skills than the person from Dell Support who was
    writing to me...

    So the problem appears to be that to enable RAID in the bios and boot from
    my current disk, I need the driver installed in the OS but the driver
    refuses to install because I'm not in RAID mode... but I'm sure there's a
    solution, I just haven't found it yet and I'm again up too late...

    Thanks for your help.
    Jerry Hoffmeister, Nov 20, 2008
  12. 1 way - switch to RAID mode, then do a "repair install" and press F6 during
    the initial stage of it to get asked to load a driver.
    Charlie Russel - MVP, Nov 20, 2008
  13. Jerry Hoffmeister, Nov 24, 2008
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