Re: [tlug] Replacing software-raided disks with dd, underlying-partitions-and-all: Will this work?

[Christian Horn <chorn@example.com>]

On Fri, Mar 26, 2010 at 03:01:44PM +0900, Edmund Edgar wrote:
> I've got a Linux server (which I'll call "server 1") with a pair of
> disks divided up into partitions, then the partitions paired up into
> RAID 1 partitions using software RAID. (No LVM in between or
> anything.)
> 
> Dell no longer sell disks of the original size, so I thought I'd take
> the opportunity to buy a new pair of bigger disks top put in server 1,
> and move the surviving disk from server 1 to server 2.

> 1) Check my backups
> 2) Replace the dead disk (sda) in server 1 with a new, bigger disk,
> boot from a LiveCD and do:
> dd if=/dev/sdb of=/dev/sda

I am not sure the exact same stuff is on both discs, mdadm-headers
or such could be different.

- I would here swap the new disc in, still having the system running.
- Copy partitiontable onto the new disc 
- take the partitions of the new disc into the raid1
- install bootloader on new disc
- run system down
- try to boot the server with only the new disc.

Should keep the downtime down and you can do the migration in single
steps.

Christian