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I'm in weird situation, where I bought 3TB drives, only to discover that server's bios does not support it (should have done my homework)...

But I still need to install them in the server, and boot from them. I was thinking there should be some way to format the disk or something like that so that BIOS would work with it. But that does not seem to be a popular topic, so search does not yield many info...

The set up is like this: I have 3 HDD slots, and I intend to install CentOS onto the drives in a software raid 5 configuration. Any idea how I can do it? When partitioning at install time - I'm given a message that bios won't load (even if splitting into under 2TB partitions), and can't proceed.

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buy a new motherboard? :) I think you're out of luck here but I'm curious what others may say. – egorgry Apr 13 '11 at 17:01
That might be even more problematic =) Better to get a new box from dell outlet or something. – Sergey Apr 13 '11 at 17:03
up vote 3 down vote accepted

BIOS will be your stumbling point. MBR-style boot reads the first sector of the first hard drive. For a 3TB drive, that first sector is likely to be 4KB, and not 512b like it has been since the dawn of PC computing. If BIOS isn't set up to deal with that, it simply will not boot. An updated BIOS will be required to handle it, if such is even available.

That said, if the BIOS can handle a 4KB sector size, or is actually counting on an EFI BIOS and still has 512b sectors (don't know if this critter even exists), it should boot.

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So, are you saying that BIOS not being EFI will not be able to boot from the drive just by definition? No ability to reformat and make first sector 512b? – Sergey Apr 13 '11 at 17:16
Sector size is set at the factory, I'm afraid. I don't know if traditional BIOS has been extended to handle 4KB sector-sizes, but that will need to happen before a non-EFI BIOS can boot from a 4KB sector-size drive. – sysadmin1138 Apr 13 '11 at 17:18
Ok, that does not seem to be a problem. According to Hitachi manual, sector size is 512 bytes. =) – Sergey Apr 13 '11 at 17:24
@Serge Great! Booting should work then. – sysadmin1138 Apr 13 '11 at 17:39
Hmm, work as in after partitioning for 2TB only? How can I achieve that, and force non-GPT? – Sergey Apr 13 '11 at 20:09

Two options that could work:

  1. Buy a PCIe controller and try booting from this.
  2. Use a smaller disk as boot drive, or even an USB stick, maybe with nothing more than the boot loader and the /boot directory.

I don't think 3TB drives are such a good idea for servers, as recovery times from RAID failues will be astronomical.

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USB stick with a /boot partition sounds like a good choice, but how can I implement this? CentOS will not allow me to install /boot on USB... – Sergey Apr 13 '11 at 17:14

Your cheapest solution would be to buy a 3rd party hard drive controller that would support your 3tb drives and be supported natively by your version of Centos.

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AFAIK, there is support in Linux bootloaders like GRUB2 for booting from GPT using BIOS. Look up the BIOS Boot Partition.

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sysadmin1138 had already pointed out why that's not the whole of the story by any means. – JdeBP May 17 '11 at 11:49

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