Requirement for quiescing guest file systems
Beginning with VRA 9.20 and Portal 9.30, you can specify whether to quiesce the file system of each VM in a backup job before backing it up. Quiescing the file system on a VM brings the data into a consistent state that is suitable for backups.
To quiesce the guest file system on a VM, VMware Tools version 11 or later must be installed on the VM.