N+1 Redundancy

High availability with data replication and application failover from N servers to 1

SafeKit HA software provides a simple N+1 redundancy cluster with N applications running on N servers and with a single backup for failover. In a SafeKit N+1 redundancy cluster, each application works on its own replicated directories.

In case of failure of one primary server unlike the active-active cluster, the backup server doesn't have to handle a double workload. This assumes there is only one failure at a time in the N+1 redundancy cluster - the solution can support multiple primary server failures at the same time, but in this case the single backup server will have to handle the combined workload of all the failed servers.

The SafeKit N+1 redundancy cluster is simply configured by deploying N mirror modules on N+1 servers. Each mirror module contains its own configuration of virtual IP address, replicated directories and restart scripts.

More information:

• HA cluster architecture
• Mirror cluster with software data replication
• Farm cluster with software network load balancing
• Clustering software with load balancing and mirroring
• Active-active cluster
• HA cluster demo
• Generic mirror module example: N modules like this one are required for an N+1 redundancy cluster