We can calculate the rest data amount. The total size can be gotten by the command below. The retset id is same with the job id.

# q retset <retset_id>

If a retset is too big to copy, you can consider replacing it with multiple smaller retsets. For example, every retset is for one nodes or two nodes. Then for every node, you can find the time when no backup work comes from it.

If you use retension set on S3 storage, as it's slow, you can have a timeout, and the job can never ended
Change the following parameter

# setopt ContainerResourceTimeout 720