The main database, catalog node and storage node services are stateful and any servers hosting these services contain critical data. It is important to replicate all such servers to maintain the availability of critical data. The application service is stateless, and therefore, any dedicated application servers do not require replication or backup. Failover between application servers is automatic.
The Nexenta edition CTERA Portal OS features a built-in replication function that you can enable when you install secondary servers to create warm standby servers. You can install any number of warm standby servers. A warm standby can replicate the content of a selected stateful server to take over in case of failure. Warm standby servers store a copy of the latest snapshot of the replicated server, which is taken every 15 minutes. In the event that a replicated server fails, you can perform a procedure to fail over to the warm standby server (see Performing Manual Failover). By default, a warm standby server doubles as an application server.
See Also |