[CentOS] Rebuilding Raid 1
peter at farrows.org
Mon May 1 22:57:39 UTC 2006
Sorry I missed out the link in my original response,
>> you might find this article useful:
Mace Eliason wrote:
> I just think this might work
> I am using scsi drives so would I use root (sd0) I tried it but it
> said error while parsing number
> I tried root (hd0) and it said filesystem type unknown, using whole disk
> I stopped at that point worried I might mess up the whole thing
> I have read other links that talk about doing it this way
> $ grub
> grub> device (hd0) /dev/hdc
> grub> root (hd0,0)
> Filesystem type is ext2fs, partition type 0xfd
> grub> setup (hd0)
> Checking if "/boot/grub/stage1" exists... no
> Checking if "/grub/stage1" exists... yes
> Checking if "/grub/stage2" exists... yes
> Checking if "/grub/e2fs_stage1_5" exists... yes
> Running "embed /grub/e2fs_stage1_5 (hd0)"... 15 sectors are embedded.
> Running "install /grub/stage1 (hd0) (hd0)1+15 p (hd0,0)/grub/stage2
> /grub/grub.conf"... succeeded
> do I need the device line first?
> Peter Farrow wrote:
>> You can replace the boot loader as follows:
>> 1)Boot in REscue mode, and get a command prompt
>> 2)Run grub, if your two disks are for example /dev/hda and /dev/hdb
>> and the boot partition is the first on each:
>> grub> root (hd0)
>> grub> setup (hd0,0)
>> grub>root (hd1)
>> grub>setup (hd1,0)
>> This will put a stage1 boot loader on each disk, you should be able
>> to boot the originally non-bootable disk now. Make sure you boot in
>> the bios from the second disk, (which I presume is the one you want
>> to keep), to make sure you could disconnect the original drive first
>> and boot the system to try it.
>> You might find this article useful.
>> If the first disk has now been fixed but contains no data, you can
>> export the partition table from the second disk using sfdisk, and
>> re-import it on the first hard disk using sfdisk again, you can then
>> use mdadm to hot add the first (replaced) disk to the second (running
>> and now bootable) disk.
>> Mace Eliason wrote:
>>> Trying a different approch.
>>> Raid 1 setup
>>> Bootable raid drive failed
>>> Mirror has been working for almost a month and then rebooted
>>> Now can't boot mirror drive grub not mirrored from other drive.
>>> I Fixed bootable drive.
>>> Can I hook up both drives and boot fixed drive then rebuilt mirror
>>> from nonbootable drive to bootable drive?
>>> Does the raid automatically rebuilt when I boot with both drives?
>>> Can I run a command to rebuilt from one drive to the other and visa
>>> I want to try it but I am worried that if I hook them up and it
>>> boots that because the bootable drive has older info it might over
>>> write the other drive.
>>> Can't seem to figure out how to get the other drive bootable.
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>>> CentOS at centos.org
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