Disable VSS backup for SQL Server

I have a SQL Server environment which is being backed up using avamar backup solution. The backup is configure such that it takes a full backup of all the disk on the VM, including the drives containing the .ldf, .mdf files. 
For reasons, I don't want to explain here, we are also running backup of the database to disk and having that backup file also copied by Avamar. What we have discovered as well is that when the Avamar backup is scheduled it is also taking a VSS SQL server backup

1. How do we disable the VSS backup for SQL server
2. How do we exclude certain volumes (drive with .ldf and .mdf ) from the Avamar VM backup