RAID 5 as boot drive.

Hi all,

I'm attempting to create a RAID5 on a Gigabyte EX58-UD5 using 4 HE753j's and using the mobo's ICH10R controller. However, whenever I create the RAID, I'm informed it is not bootable. Unsurprisingly, Windows 7 will not allow me to install to the RAID but does recognize it. I tested it out and I can create a RAID 10 just fine and its bootable. Any idea on how I can get the RAID5 to work properly? Also, I came across this thread over on Hard Forum. If you scroll down, you'll see he's also got a RAID 5 that is listed at not bootable. Can I just not use a RAID 5 as a boot drive?

Any help would be greatly appreciated.
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  1. Best answer
    Although I don't know for sure, I suspect this is a limitation of the ICH chipset-based rate. The problem is that the chipset itself doesn't actually have the logic needed to manage the RAID set - that logic is contained in the Windows driver that's loaded at boot time.

    The issue is that when the BIOS starts to boot windows those RAID drivers aren't loaded yet - so it's up to the chipset itself to understand how to read the boot sectors from the RAID volume. This is fairly simple for RAID 0, 1 or RAID 10 because the boot blocks are easy to locate on one or more of the drives, so the limited capabilities of the ICH chipset are able to handle it.

    RAID 5 is different because if there is a failed disk in the RAID set then the data has to be recreated by reading the other drives and performing parity calculations in order to recover the information. I strongly suspect the ICH chipset isn't capable of doing this on it's own, so that would mean it couldn't be used for a RAID 5 boot device.
  2. I think your theory is true. I took one drive out of the RAID (and tested all drives to make sure I didn't have a dead one) and suddenly the RAID 5 could be a boot drive. I've decided to just use 1 drive as a system and .exe drive and the other for data. Thanks for your thoughts.
  3. Best answer selected by alkuth.
  4. Not exactly what sure what the issue is, but as long as you loaded the Intel RAID drivers during the windows install (by pressing F6 when prompted) you can load the OS onto a RAID5 array using the ICH10R southbridge chipset. Of course, you would have to go into the BIOS and enable the SATA as RAID and then enter the RAID BIOS to create the disk array and then perform the OS install, and as mentioned, being sure to supply the RAID driver during the windows install.

    I've done this same procedure on Intel and nVidia chipsets as well as using dedicated RAID hardware controller cards. As long as you configure the BIOS and RAID BIOS properly, there *should* be no reason (aside from PEBCAK) why you can not install an OS onto a RAID5 array attached to the ICH10R controller.

    Think about it, why would Intel include RAID5 capability onto the mobo SATA controller chipset if you couldn't use it to load the OS onto?! They wouldn't.

    You can download the Intel RAID driver and read the associated documents and instruction on how to load the OS onto a RAID5 array at this Intel Support web page. Enjoy!

    I just can't believe the reply from sminlal was selected as "best answer"...
  5. Well, I did say I didn't know for sure! :(

    OK, so if RAID 5 is supported for booting, the problem is probably because you put so many disks together you ended up with a volume with more than 2TB of space. You can't boot from a volume larger than 2TB unless the BIOS supports GPT partitions (GPT = GUID Partition Table). See:

    Sorry for the misdirection - I should have sussed into the volume size issue first!
  6. We got it to work with 6x1TB drives on intel DP55KG by creating volume 0 as 2TB and Volume 1 as 2.5TB.
    Basically, you cannot create a bootable volume more than 2 TB
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