Pacemaker makes no assumptions about your environment, this allows it to support practically any redundancy configuration including Active/Active, Active/Passive, N+1, N+M, N-to-1 and N-to-N.
Two-node Active/Passive clusters using Pacemaker and DRBD are a cost-effective solution for many High Availability situations.
Figure 1.1. Active/Passive Redundancy
By supporting many nodes, Pacemaker can dramatically reduce hardware costs by allowing several active/passive clusters to be combined and share a common backup node
Figure 1.2. Shared Failover
When shared storage is available, every node can potentially be used for failover. Pacemaker can even run multiple copies of services to spread out the workload.
