CentOS List wrote:
CentOS List wrote:
I am running raid 1 on a centos 4.4. One of the harddisk (sda1)
failed. How can i carry on running the server using only sda2?
Generate a grub floppy and use that to load the grub menu from the
sdb (probably now sda) disk.
If you are really talking about sda1 and sda2, those are partitions
on the same disk.
Is there a detail step by step howto? The raid 1 has no LVM. just
md0, md1 and md2. md0 is /boot, md1 is swap and md2 is the storage. I
had replace sba with a new disk. I tried to boot up and it says
kernel panic. How am i going to reconstruct the raid and sync sdb to
sda?
It might be easier to swap the old sdb into the sda position so you'll
boot from it, but you should also be able to boot the install cd with
If swapped and booted, and got a kernel panic error.
'linux rescue' at the boot prompt, let it detect and mount your system
(which will be the 'broken' raid devices with their single members),
If i use linux rescue, The 3 mds I created are gone. /cat /proc/mdstat
says Personalitlies: [raid0] [raid1] [raid5] [raid6], no longer
Personalities : [raid1]
Perhaps your raid wasn't really working the way you thought before. From
the rescue boot, does fdisk show the 3 partitions on the old disk with
type 'fd'? Can you mount the old /boot and / partitions somewhere by
hand? You should be able to do this with the /dev/sda1 and /dev/sda3
device names if the md devices aren't detected at boot.
cat /proc/partitions still shows me the 3 partitions.
Does fdisk say that they are type 'fd'(raid autodetect)?
I actually copied /boot to the "replaced disk" and it is able to boot up,
but without any filesystem, so i guess the boot is still intact. So do i
need to mount /boot and /?
If you can get the original partitions to be detected as their md devices
you should fdisk matching partitions on the replacement disk, then
'mdadm --add ...' to add them and they will automatically sync up.
mdadm --create --verbose /dev/md0 --level=1 --raid-devices=2 /dev/sda1
/dev/sdb1
mdadm --create --verbose /dev/md1 --level=1 --raid-devices=2 /dev/sda2
/dev/sdb2
mdadm --create --verbose /dev/md2 --level=1 --raid-devices=2 /dev/sda3
/dev/sdb3
After that i reboot and got the kernel panic again.
md: considering sdb1
md: adding sdb1
md: created md0
md: bind<sda1>
md: running: <sdb1><sda1>
raid1: raid set md0 active with 2 out of 2 mirrors
md: ... autorun DONE
md: autodetcting RAID arrays
md:mautorun ...
Creating root device
Mounting root filesystem
switching to new root
switchroot: mount failed: 22
umount /unitrd/dev failed: 2
Kernel panic
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