Backup running very slow

Hi Experts,

I need your urgent assistance on a long running backup, below given are the details.

Master OS : Linux Master NBU Version : 7.0.1

Client OS : Windows Client NBU Version : 7.0.1

Issue : Backup of few drives taking more than 70 hours to complete. 

Data size is around 2 Tb.

12172 Kb/sec is throughput getting for backup.

How can I make the backup run fast, and what could the reason for slow backup. What are the steps to troubleshoot.

Would really appreciate your reverts and assistance