[olug] Mirroring a boot drive

[Ben Hollingsworth]

I've got a Ubuntu system (currently 16.04, but soon 18.04) with a 
single, 5.5-yr-old SSD boot/root drive and a handful of other disks in a 
RAID5 data array.  I'd like to add a second boot drive to create a RAID1 
mirror, since the current boot drive won't last forever.

There are plenty of instructions available for installing a fresh Ubuntu 
server install on a RAID1 partition.  However, I need to keep & upgrade 
my existing install, since it's heavily customized.  I can't find any 
instructions specifically for this scenario.  Have any of you ever done 
this?

The idea I've had is to install the new disk and unplug the existing 
boot disk.  Install a fresh 18.04 server release using the new disk and 
some spare space from another old disk as the mirrored pair. Once that's 
running, copy the old boot drive's data on top of the new boot drive 
(this is the part I'm not sure will work well).  Once the new 
drive/mirror is set up with my old OS, remove the old spare drive from 
the mirror and replace it with the old boot drive.  Yes, I have multiple 
backups.

Does that sound plausible?  Is there a better way?

I suppose the alternative is to just keep running off a single drive, 
and replace the old one as soon as it throws the first SMART error.  
That makes me nervous, though.

-- 
*Ben "Obi-Wan" Hollingsworth* obiwan at jedi.com <mailto:obiwan at jedi.com> 
www.Jedi.com <http://www.jedi.com>
The stuff of earth competes for the allegiance I owe only to the
Giver of all good things, so if I stand, let me stand on the
promise that You will pull me through. /-- Rich Mullins/