Backup before reinstall

[Christian Baer]

Greetings Programs! :-)

One of my boxes is still running FreeBSD 10. Everything is updated to
include the latest patches, but the time has come to move on. :-)

Trying an update over multiple major releases is almost guaranteed to
break the system - even if it's done in steps - so I have decided to
reinstall everything. This will also get rid of some redundant stuff I
have installed.

This machine is used as a server and I haven't installed X at all. What
I do utilize heavily is Geli and ZFS (als RAIDZ2).

I don't mind reconfiguring a few things on foot after the reinstall.
But I really want to be able to access my encrypted RAIDZ again. :-)

The system boots from a 128GB SSD. This holds all the partitions for /,
/usr /var and swap. Nothing on the SSD is encrypted, because I want the
system to be able to boot without any "help". This is the only physical
device that will get erased during the reinstall.


The raidz has it's own mountpoint (under /zfs) and contains three
subvolumes, which are mounted in different places (one of them is
/home). The raidz spans seven HDDs, which are all encrypted with geli.
To be clear: The drives were encrypted first and the raidz spans the
encrypted (.eli) devices.

The setup isn't really too complicated. What I don't know is where
FreeBSD stored the information about what belongs to the raidz etc. Is
there something special I need to backup to be sure all of this is
reusable again?

I could of course backup the whole SSD. But there is a lot of junk
there I won't need again (most of the data probably), so if I can, I
would try to only backup the useful stuff.

I would appriciate any advice!

Cheers!
Chris

P.S. Before anyone tells me that backups are important: I have backups,
but only of the data on the raidz. This is what I considered to be
important, not so much the system. So if this goes wrong, I could
restore everything, but that would take much longer than I'd care to
sit in front of the computer. :-P