backups of bhyve images

[John]

Hello list,

I have a few questions about creating backups to be stored offsite.

If a guest is running, can I compress the image without it becoming 
inconsistent? If not, can it be copied without it becoming inconsistent?  
By inconsistent, I mean will I see weird effects and broken files if the 
backup is restored? Previously I've shut the VM down to avoid this, 
before archiving.

I have each image on its own (external to the image) ZFS filesystem.  
Internally the image is using ufs if freebsd, ext3fs if linux.  Would 
using some ZFS method of duplication be better? In this case, would the 
image become inconsistent?

Basically, what I want to do is to run accurate backups without shutting 
down and restarting the VM. Is this possible? If it isn't, I think the 
only alternative is to make a script that shuts the vm down, copies it, 
restarts the vm then runs its compression and backup-over-ssh routine.

thanks,

-- 
John