The 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.
As an example, see the following video demonstrating the deployment of one mirror module with Microsoft SQL Server 2012 R2. The operation can be repeated with other mirror modules and with other applications.