I started a similar thread several weeks ago: Sever software shut down in the middle of the night (must not have seen this one).
I’m not convinced the network copy is totally responsible for the length of time the backups are taking. My first backup took nine hours for 150gb. This was just going to local disk, no network copy was involved. As a wild guess, I think maybe the encryption and or compression is responsible.
As a comparison, the same data on my old server took about two hours to send compressed tar files to another in-house server. This was done from an LV snapshot of the volume so there was no down-time.
Has anyone tried creating a snapshot on an MaiB box?