[CentOS] raid 1

[Les Mikesell]

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.

-- 
   Les Mikesell
    lesmikesell at gmail.com