Help with external snapshots as backups

[Alex Regan]

Hi,
I have a win10 guest on a fedora32 system and have some questions as I 
explore using external snapshots as a form of backup in case of a 
Windows failure (as in, it won't boot or is completely irrecoverable) as 
well as revision control (to be able to rollback changes after a failed 
app install, etc).

The first hit on Google for external snapshots involves a RHEL7 document 
that talks about how it's not officially supported. The current RHEL8 
docs don't include any references to snapshots.

The fedora docs I've found are many years old - I'm just not sure if 
they're still applicable. Where can I find the current docs for fedora32?

- If I've already created a live internal snapshot, can I then create an 
external safely? Are all changes currently being written to this 
internal snapshot now?

- Can external snapshots be used for backup? Perhaps there are 
predefined steps for doing this that I can follow?

This is the procedure I'm currently using. I've made a backup of the 
original image - can I now just continue to backup the snapshots in the 
eventuality of a crash, then use this original image backup and the 
snapshots to restore it?

I suppose I would also periodically merge the snapshots back into the a 
single snapshot to ease the process?

# virsh snapshot-create-as --domain dave-win10a win10a-state01 
--diskspec 
vda,file=/var/lib/libvirt/images/vm_snapshots/disk-overlay.qcow2,snapshot=external 
--memspec 
file=/var/lib/libvirt/images/vm_snapshots/mem-overlay.qcow2,snapshot=external 
--atomic
Domain snapshot win10a-state01 created

# ls -lh vm_snapshots/
total 3.3G
-rw------- 1 qemu qemu 196K Jul 11 12:32 disk-overlay.qcow2
-rw------- 1 root root 3.3G Jul 11 12:32 mem-overlay.qcow2

Thanks,
Alex