Special instructions must be followed to install ZCB on a Read-Only Domain Controller (RODC). These instructions are largely centered around the amandabackup user.
The amandabackup user is an integral part of ZCB functionality. Please see What is the amandabackup user? for more details.
By definition, users cannot be added to Active Directory on a Read-Only Domain Controller. The amandabackup user must be created on another machine on the domain. ZCB cannot be installed on a RODC until amandabackup is created as a domain user.
There are two options available to create the amandabackup user in Active Directory prior to installation on a Read-Only Domain Controller.
The amandabackup user can be created automatically. Simply install ZCB on another machine on the same domain as the RODC. If no amandabackup user exists, the installer will attempt to create it.
You must choose to create amandabackup as a Domain user during this step. Creating a local amandabackup user is not sufficient.
The machine used for this purpose must not be a Read-Only Domain Controller.
The amandabackup user can be created manually by following these steps.
It is only necessary to create the domain amandabackup user once on any given domain. Once created, any subsequent ZCB installation on any machine, including Read-Only Domain Controllers, will detect the domain amandabackup user and prompt for the password.
Thus, if ZCB needs to be installed on multiple Read-Only Domain Controllers in a single domain, Step 1 only needs to be performed once. All subsequent RODC installs can begin with step #2.
In most cases, users added to Active Directory will automatically appear on other Domain Controllers, including Read-Only Domain Controllers, via scheduled replication processes.
Replication can be triggered manually between Domain Controllers using the Active Directory Site and Services tool.
Once amandabackup is available on the RODC, install ZCB.
During installation, the domain amandabackup user created in step 1 will be detected. The installer will prompt you for the user password.
Enter the user password. Installation will proceed.
Once ZCB is installed, configure your backups!
All backup types are available on a RODC, just like any other Windows machine.