Boot from software RAID. Sarge. Kernel 2.6.5. SATA.
Hello,
I am trying to setup server with RAID 1. I got RAID working but I am
having problems booting from it.
Unfortunately box I am working on is quite dumb, only two drives can be
connected to it and it can boot only from first drive.
I installed minimal system on first drive, I can create RAID1 on
non-root partitions, and it gets detected after reboot, can be mounted, etc.
Now I want to set raid on root partition.
I created partition on second drive of exact same size as root partition
on first drive. Created a degraded RAID1 array out of it (with first
drive missing). Copied contents of root partition on new array
(/dev/md0). Changed fstab on new partition to mount /dev/md0 as root.
First question: I copied root partition by logging into Knoppix and
issuing 'dd if=/dev/hdc1 of=/dev/hdd1' command -- effectively bypassing
RAID since Knoppix does not appear to have raid support. Is it ok? Or
should I rather create an image from Knoppix and then dd it to /dev/md0
from Debian?
Now I am trying to figure out how to boot from raid. Since I can't
really boot from second drive, I decided to try booting from first drive
using raid array as root partition.
I added entry to my lilo config, named "LinuxRaid". It exactly the same
as my regular "Linux" entry, with addition of "root=/dev/md0" parameter.
System starts booting fine, but at the end I get kernel panic.
Relevant log lines (note: i am retyping log by hand):
md: raid1 personality registered as nr 3
md: multipath personality registered as nr 7
md: md driver 0.90.0 MAX_MD_DEVFS=256, MD_SB_DISKS=27
device-mapper: 4.1.0-ioctl (2003-12-10) initialised: dm@uk.sistina.com
[snip]
md: Autodetecting RAID arrays.
md: autorun ...
md: ... autorun DONE.
EXT3-fs: unable to read superblock
EXT2-fs: unable to read superblock
isofs_fill_super: bread failed, dev=md0, iso_blknum=16, block=32
UDF-fs: No partition found (1)
Kernel panic: VFS: Unable to mount root fs on md0
When I boot from my regular root partition dmesg reports following:
md: raid1 personality registered as nr 3
md: multipath personality registered as nr 7
md: md driver 0.90.0 MAX_MD_DEVS=256, MD_SB_DISKS=27
device-mapper: 4.1.0-ioctl (2003-12-10) initialised: dm@uk.sistina.com
[snip]
md: Autodetecting RAID arrays.
md: autorun ...
md: ... autorun DONE.
kjournald starting. Commit interval 5 seconds
EXT3-fs: mounted filesystem with ordered data mode.
VFS: Mounted root (ext3 filesystem) readonly.
[snip]
EXT3 FS on sda1, internal journal
md: md0 stopped.
md: bind<sdb1>
raid1: raid set md0 active with 1 out of 2 mirrors
So looks to me like RAID array gets activated after root partition is
mounted. Any ideas how to handle this problem?
--Kirill
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