I have 2 Xen hypervisors on Linux with virtual machines running off an NFS export from the FreeNAS server. The virtual machines are raw img files stored on a ZFS dataset. Previously, I looked into snapshotting virtual machines with LVM which led me to the below link published directly on the Xen project wiki:
The process outlined in the above link includes; pauses the virtual machine, takes a snapshot of virtual machine, mounts the snapshot, syncs the snapshot to backup media, umounts snapshot, removes snapshot, resumes virtual machine. With ZFS I know I can achieve better functionality with snapshotting/replicating but would like to go about it the correct way following the Xen standards.
I have a couple questions:
- Do Xen virtual machines have to be paused for snapshotting?
- Out of the box, will ZFS replication give me reliable backups of my virtual machines?
2a. If not, are there any hooks for the ZFS replication or in FreeNAS to allow a custom script (I.e. one to pause/resume a virtual machine) to be ran before snapshotting? Or would this process even be needed?