Replacing both disks in RAID1

[Toomas Aas]

Derek wrote:

> Toomas Aas wrote:
> 
>> 1. Attach one of the new drives to free ICH4 IDE port on motherboard, 
>> partition it and transfer the data using dump/tar.
> 
> 
> At this stage, I would recommend doing this in single user mode, to keep 
> filesystem modifications during the procedure down.  

Yes, that was my plan. Definitely a good idea.

> I typically use dump for all partitions when in single user mode like so:
> 
> #adjkerntz -i
> #swapon -a
> #mount -a
> 
> ...
> #mount /dev/ad0s1a /mnt/newroot
> ...
> 
> /mnt/newroot# dump 0af - / | restore xf -
> /mnt/newtmp# dump 0af - /tmp | restore xf -
> ...etc

I need to use tar for some things, since I'd also like to re-arrange 
partitioning a bit. I think I have that part figured out, including how 
to make all the daemons happy with new locations for the data.

>> 2. Remove the 80 GB drives, attach 200 GB drives (one with data, one 
>> blank) to TX2 IDE ports and re-create the mirror using Promise onboard 
>> BIOS utility.
> 
> 
> I would go with this if you can afford the time.  On servers that we 
> don't want down for long, I recreate the mirror in the BIOS, let it 
> mirror to 1%, and then reboot (ignoring the RAID error), and start 
> rebuilding with atacontrol.  It still takes a while, and the server is 
> slow because of the excessive disk i/o, but it is responding.

I'm planning to do this on Saturday when downtime is not that big an issue.

>> 3. Reboot, fix the fstab (if necessary) and be done with it.
> 
> 
> Shouldn't need a reboot/mess with fstab if you are careful.

If I'd left the partitioning the same, then yes, but I do want to do 
some changes there.

>  From my experience with the Promise cards, this is the way to go.  I've 
> had to upgrade serveral machines, as we've been using the cards in 
> production.

Thanks for confirmation. I sleep better tonight.

> The one caveat that I would warn you about is making sure that all your 
> corresponding partitions line up, to prevent having to mess with fstab 
> (and have the data in the same relative physical location on the drive)

But if it is necessary, it should be possible to bring the machine up to 
single user mode and modify the fstab there, right? Given, of course, 
that the root partition is left on ar0s1a.

Thanks a lot,
--
Toomas