Maybe another approach… Wouldn’t it be possible to copy/move the dom0 root pool LV to your external HD (offline, via a LiveUSB). Double check the UUID’s and adjust /etc/fstab and /etc/crypttab if necessary.
Then re-install grub
just thinking out loud here, no experience.
(if you do choose this approach, would you mind keeping notes and sharing them as I want to do something similar and I have no idea how (and low priority atm)).
What I would like to do when I have the time, is make some kind or raid for my SSD’s, but instead of having a ‘hot’ raid with lots of read/write operations that wear both SSD’s down at the same rate… I want a ‘cold’ raid where one SSD wears down normally and the other get’s used once every month or so.
- with ‘hot’ raid I mean a normal raid1 setup
- with ‘cold’ raid I mean duplicate the dom0 pool on other PV2, make dual-boot, create snapshot only run dom0 on PV1 storing changes in snapshot. Once a month copy snapshot to PV2, merge snapshots, and start a new one on PV1.
Maybe merging the snapshots is not necessary… maybe we can have snapshots after snapshot after snapshot, like:
PV1: [snapshotted dom0][October’s snapshot][November’s snapshot][current snapshot]
PV2: [snapshotted dom0][October’s snapshot][November’s snapshot]
And in January I start a new snapshot on PV1 and copy [December’s snapshot] to PV2
That way I extend the lifetime of PV2, and if PV1 fails, I’m only one month’s updates behind.
But as I said… no experience here. I used to do something similar in Ubuntu a decade ago… but that was on partition-levels (pre LVS), and back then I didn’t use LUKS.