When you backup SQL with TDP agent (only for legacy method), you can use buffering parameters and stripes so that improving data transfer rate of SQL databases could be possible.
The number of buffers that Data Protection for SQL allocates to the read and write threads can be specified in the /buffers (3 by default) and /sqlbuffers (0 by default) parameters of the command line interface. The size of these buffers can be specified in the /buffersize (1024 by default) and /sqlbuffersize (1024 by default) parameters. Inaddition to this /Stripes (1 by default) parameter determines the number of sessions in TSM Servers.
For example, you can use these parameters in your tdpsql.cfg file to backup SQL databases with 5 sessions;