Backup speed is limited by the slowest component in the data flow, this is also known as bottle neck.
To find the bottle neck, a series of tests is needed.
Let´s start with the read speed of your disk.
Windows:
The follwing command will read the data from disk E:\ and measure the performance.
vbda -vol e: -out nul -profile
The following command will read the data from disk E:\ - limited to the directory snoopy - and measure the performance.
vbda -vol e: -tree \snoopy -out nul -profile
Linux:
The following command will read the data from a file system called "home" and measure the performance.
/opt/omni/lbin/vbda -vol /home -out /dev/null -profile
The following command will read the data from a file system called "home" - limited to the directory snoopy - and measure the performance.
/opt/omni/lbin/vbda -vol /home -tree /home/snoopy -out /dev/null -profile