Forum Discussion
Azure AD Connect Backup and restore.
According to your AAD connector design as fault-tolerance in which primary server as export to sync to O365/Azure AD from On-Prem to azure and staging has read-only export where you can rollback for any crit-sit.
However, taking VM level backup using azure native backup or MABS or thrid party integrated solution using VEEAM VM azure backup is highly resilient for restoring the VM in case of OS corrupt or application corrupt.
The following article is defined about the backup configuration of AAD which would also helpful for your backup scenarios.
https://github.com/Microsoft/AADConnectConfigDocumenter
Note: Azure AD Connect requires a SQL Server database to store identity data. By default, a SQL Server 2012 Express LocalDB (a light version of SQL Server Express) is installed. SQL Server Express has a 10-GB size limit that enables you to manage approximately 100,000 objects. If you need to manage a higher volume of directory objects, point the installation wizard to a different installation of SQL Server.