If the NSX Manager cluster becomes inoperable, or if you want to restore your environment to a previous state, you can restore from a backup. While the NSX Manager is inoperable, the data plane is not affected, but you cannot make configuration changes.

There are two types of backups:
Cluster backup
This backup includes the desired state of the virtual network.
Node backup
This is a backup of the NSX Manager nodes.
There are two backup methods:
Manual
You manually run the backup at any time.
Automated
Automated backups run based on a schedule that you set. Automated backups are highly recommended to ensure that you have up-to-date backups.

You can restore an NSX-T Data Center configuration back to the state that is captured in any of the backups. When restoring a backup, you must restore to new NSX Manager appliances running the same version of NSX Manager as the appliances that were backed up.