Active-Active disaster recovery configuration
Once the catalog replication is configured, you can use site specific backup policies to perform local backup and use duplication policies to replicate backup images to remote cluster for protection against site outage. The clients communicate with the primary server on the primary site for sending metadata and communicate with media servers available on local cluster for sending backup data. The clients that are located at the primary site should use the local STU available at the primary site for backup and use the remote site's STU for duplication. Similarly, the clients that are located at the secondary site should use the local STU available at the secondary site for backup and use the remote site's STU for duplication. This way, it is ensured that duplications are performed across the sites for local backups. After disaster recovery configuration, the STUs of both the sites are always available for backups and duplications. Default SLPs are created as a template to configure backups and duplications at each site. The NetBackup administrator can use the default SLPs or can create new SLPs based on the template to perform backup and duplication.
Active-Active disaster configuration can be done from the NetBackup primary server using the web UI or the NetBackup Java GUI.
When any disaster happens, such as the primary site goes down for some reason, the clients at the primary site will not be able to continue the backups at the primary site as the local STU will not be available. The clients at the secondary site will also not be able to perform duplications as the remote STU will not be available for duplications. The backup jobs for primary site clients will fail or remain in waiting state for the STU to become available. The duplications jobs from secondary site clients will also fail or remain in waiting state for the STU to become available. The same situation arises when the secondary site is down due to any disaster.
When any disaster happens at a primary site, the secondary site is the only available site and must become the primary site so that the NetBackup primary server is available for the clients and pending jobs can be resumed or restarted. The takeover operation needs to be performed to make the secondary site as the primary site. Once the site becomes primary, the duplication jobs of old primary site are resumed/restarted and completed. The clients at secondary site continue to perform backup as the local STU is available for backups, but duplication jobs will remain in failed/waiting state.
Note:
The NetBackup administrator can make the backup storage as the new primary site's STU until the old primary site is available so that the client backup jobs of the old primary site can be completed. This can be done by making the primary site's SLPs to point to the new primary site's STU as backup storage.
Important: When the site role changes, the clients residing in domains other than the NetBackup Flex Scale disaster recovery domain may be required to update the host entries in the NetBackup configuration to connect to the media servers of the site.
If disaster recovery is configured and the primary site requires maintenance or updates, it can be switched to the role of secondary site using migrate operation. When the migrate operation is performed, the primary site becomes the secondary site and the secondary site becomes the primary site without affecting the backup and duplication jobs of the client. The NetBackup administrator does not have to change the SLPs since both the sites are up and the NetBackup primary service is also available. The clients at both sites will continue to do backups (to the local site STU) and duplication (to the remote site STU).