Linux – nyway to do a live qcow2 backup without pausing vm’s

This might not be possible in your situation, so I hope I don't get down-voted in that case, but it might be more efficient to change your backup strategy. If you back up specific data instead of VM snapshots, your backups would run much quicker, and it would be easier to capture changes.

Depending on your VMs and what they're used for, you can just have them back up data to where you store the snapshots now daily (or whatever schedule is appropriate), and then JungleDisk can back up just the data. That would more efficiently transfer changed files, and the space required for backups as well as time needed would be reduced. In addition, you could still take snapshots to retain, and just do that much less often (weekly, for example).

In this case, you could always just bring up a new VM and restore data, or use an older snapshot to restore the VM, and then use the data backup to restore to the most recent point.

Have a look at rsync and rsnapshot. Rsync has many options and you can easily integrate it into a script or/and add it to your crontab (this is a bit of DIY).

For your needs however I would use rnsapshot (it uses rsync) it can normally do everything you want.

rsnapshot is an rsync-based filesystem snapshot utility. It can take incremental backups of local and remote filesystems for any number of machines. rsnapshot makes extensive use of hard links, so disk space is only used when absolutely necessary.

Using hard links, rsnapshot creates the illusion of multiple full backups, while only taking up the space of one full backup plus differences. When coupled with ssh, it is possible to take snapshots of remote filesystems as well.

Consequently, rsnapshot saves much more disk space. The amount of space required is roughly the size of one full backup, plus a copy of each additional file that is changed.