Erwin van Londen
Whenever you experience problems with your backup regarding performance and low throughput values, take a good look at your servers. I had a problem with slow backup speeds on a SAN. Usually I had to receive about 350 MB per minute, but suddently the throughput dropped down to about 30 MB per minute.
After analyzing the problem, I discovered that a colleague of mine made a change in the antivirus software on the server so that all outbound traffic had to be scanned before transmitting it. You can imagine that on a 1 TB SAN, this can take awhile! After reconfiguring the antivirus software, everything went back to normal.
If you have any software that is monitoring traffic or are doing something like antivirus software, discontinue it during backups, or at least do not track and trace outbound traffice during that time.