Redundancy and resiliency are often confused. They are related, but not interchangeable. Redundancy is something that is done to prevent failure, implying that it happens before an issue happens. Resiliency, from the word resolve, relates to how to find solutions after a problem has occurred. Redundancy is before the issue. Resiliency is after. For example, redundant databases with replication can be utilized. Multiple components and copies of data create a redundant design. If the primary side of the database pair fails, the secondary side will promote to primary and begin to pick up the load while the failed side self-repairs. The failover and self-healing functions are resiliency. Both are related, but not ...
