An implementation only in the backup job would be great, that would fit my needs. Maybe some more flags in the backupxml file would be useful. I used for compressing on the zstd call "--sparse --rsyncable -B128 " as the files are later transfered with rsync. The compression level would also be useful to set. By the way, is the backup qcow2 file written from qemu or from libvirt, when calling backup-begin ?
