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I'm installing Gentoo on a SOHO server with 4 500GB Hitachi hard drives.

I was able to boot from Live USB, created RAID-10 array /dev/md0 with the following command:

mdadm --create /dev/md0 --assume-clean --level=10 --raid-devices=4 /dev/sda /dev/sdb /dev/sdc /dev/sdd --metadata=0.90

After that I created three partitions with fdisk

Disk /dev/md0: 1000.2 GB, 1000214626304 bytes
2 heads, 4 sectors/track, 244193024 cylinders, total 1953544192 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 524288 bytes / 1048576 bytes
Disk identifier: 0xdcf44765

    Device Boot      Start         End      Blocks   Id  System
/dev/md0p1   *        2048       67583       32768   83  Linux
/dev/md0p2           67584     8456191     4194304   82  Linux swap / Solaris
/dev/md0p3         8456192  1953544191   972544000   83  Linux

Then I created filesystems with mkfs.ext2 /dev/md0p1, mkswap /dev/md0p2 and mkfs.ext4 /dev/md0p3 respectively:

/dev/md0p1      /boot   ext2    defaults,noauto,noatime 0 2
/dev/md0p2      none    swap    sw                      0 0
/dev/md0p3      /       ext4    noauto,noatime          0 1

After that the whole installation process by handbook went just fine, I've even installed mdadm and lvm2 and added them to boot runlevel.

When it came to choosing bootloader I got stuck. I've heard that GRUB 0.97 is unable to handle RAID-10 arrays, the same is with LILO.

I've installed LILO, and after running /sbin/lilo it said that it is able to run from RAID-1 volumes only...

What should I do? I've reinstalled Gentoo three times already. First was with Fake H/W RAID, second with 1.2 Superblock version, third with 0.9 Superblock version.

I know that I'm somewhat close to reaching the goal, but I need help on choosing the right bootloader.

UPDATE: I was able to setup boot with GRUB2, but now I have another problem. During the boot I see this message:

Operating system missing

I guess it's because on a hardware level I just have 4 AHCI HDDs and BIOS doesn't know which one contains boot sector...

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1 Answer 1

up vote 1 down vote accepted

Regardless of the bootloader, the raid level or the raid software you use, when you set up a software raid you will need to create at least a boot partition (typically /boot) which is NOT part of the raid. This is because the system's bios is not aware of the existence of the raid and in order to see the raid you first need to load the kernel and the raid software which is part of the kernel.

For more information please take a look at this:

By the way it's not that difficult to make your current system bootable. If you do not want to re-install and re-create the software raid you can add a 5th disk to the system which you will boot from. This disk, or at least one partition of the disk, should not be part of the raid.

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Thanks a lot! Amazing guide there!!! –  user135199 Mar 5 '13 at 2:33

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