Disaster Recovery

You can use the disaster recovery feature to resume FTL communications after the main operations site becomes disabled. Application systems can continue after the interruption using replicated persistence data at a remote disaster recovery site.

Prepared for Disaster

The first diagram illustrates a set of FTL servers configured to prepare for recovery from a potential disaster, along with the services they provide and the application processes that they serve. Servers at the main site are on the left (green). Components at the disaster recovery site are on the right (orange).

At each site, each of three core FTL servers explicitly provides a realm service (blue pentagon). Similarly, three auxiliary servers provide a cluster of persistence services (purple hexagons).

Note: The main site must configure the persistence services in separate auxiliary servers, and not in the core servers.

Application processes run only at the main site. An application can connect to any local core server (blue lines).

For persistence functionality, the core servers direct applications to the local auxiliary server that provides the persistence cluster leader (red ellipse).

Within each site, the realm services and persistence services synchronize to the state of the local cluster leaders.

The cluster leaders at the two sites communicate via WAN link, to synchronize the disaster recovery site with the latest realm definition and persistence data.

After Recovery

In the second diagram, a disaster has disabled the main site. Administrators have manually cut over to the disaster recovery site:
  1. Administrators have reconfigured the standby set of persistence services to be the primary set.
  2. Administrators have restarted the disaster recovery FTL servers as the new main servers (green).

The disaster recovery site now operates as the new main site. Applications connect to the primary servers and communicate with the persistence service in the cluster leader (red ellipse).

Administrators can begin to set up another disaster recovery site.