I have a couple of Windows 2003 servers backing up through 1GB line to my Windows 2008R2 networker server with Networker 8.1.1.4 installed. Backups are running to LTO5 tape drive. Both 2003 servers are VM and have C,D,E,F and Z drives. I noticed backup on D and Z drives are very slow, I'm getting on average around 6-7 MB/s when the other drives are streaming with ~20 MB/s. D has many small files and maybe causing the slowness but Z drives have 10-12 DBF oracle DB with 2GB on each file. When Z drive running alone, it only backup with speed 4-6 MB/s. But when I start another group with other Windows 2008 client in there, the Z drive will start to pick up the speed itself, sometime getting up to 20-30 MB/s. You can see the picture attached. I already hardcoded network switch to Full instead of Auto-Negotiate

I try manually copy one of the DBF file with 2GB size and the rate is very good with ~30MB/s. I'm not sure what is going on here.