We can create a fullback of oVirt engine without stopping the oVirt infrastructure using the ovirt-backup command.

To do this, ssh to the oVirt hosted-engine and specify this backup scope, the name of backup file and the name of the log file.

[root@ovirtm ~]# engine-backup --scope=all --mode=backup --file=ovirtm-backup_20201223.tgz --log=backup_20201223.log
Start of engine-backup with mode 'backup'
scope: all
archive file: ovirtm-backup_20201223.tgz
log file: backup_20201223.log
Backing up:
Notifying engine
- Files
- Engine database 'engine'
- DWH database 'ovirt_engine_history'
Packing into file 'ovirtm-backup_20201223.tgz'
Notifying engine

There is more in-depth explanation on how to do the backup of hosted-engine available at Red Hat Customer Portal.