Disk Recovery Part III

[lug at the-leveys.us (Don Levey)]

discuss-bounces at blu.org wrote:
> Don Levey wrote:
>> Hmm... Mirror the /boot partition too?
> Why not?  It's critical to booting your system...
> The only reason not to would be if your boot-loader couldn't grok raid
> partitions (I know grub can).
>
OK, I guess I *can* do that.

>> Can I RAID these devices while the system is running?  That is, boot
>> off the first of the two drives, edit the /etc/fstab to take the new
>> partition names (md2, md3, etc) into account, edit the /etc/raidtab
>> file to add the new RAID partitions, and then run mkraid on the
>> running drives/system to synch up? Is that all there is to it?
>> Somehow it seems too easy.
> Um, you can't (safely anyway) take an existing filesystem and make it
> RAID.  Doing mkraid will (potentially) corrupt your filesystem.
>
> What you could do is configure a RAID-1 disk with no mirrors, create
> your filesystem, copy files, etc.  Then reboot with root=/dev/md#, and
> *then* you can hot-add a mirror (your other disk).
>
Ah, then I can configure this disk as RAID-1 while still booted to the
original disk.  I can live with that.

>> At the very least, I can probably get an FAQ out of this, though
>> looking at the BLU website I don't see an FAQ section.
>
> http://tldp.org/HOWTO/Software-RAID-HOWTO.html
>

Actually, I was referring to one on how to deal with this sort of situation
(replacing partially-corrupted system disk) rather than a more general RAID
how-to.
 -Don