Failover and failback considerations
These basic rules apply to replication, failover, and failback on replication links, regardless of the replication topology:
- Multiple failed-over active/active links in a replication topology can be failed back in any order.
- With failback of multiple failed-over active/passive links in a replication topology, order matters.
- If a topology includes both failed-over active/active links and failed-over active/passive links, order matters for failing back the active/passive links, but the active/active links can be failed back in any order and at any time.
- With active/passive links, failover occurs from the primary system to the replica for the same link. Failover cannot occur from the primary system for one link to the replica for a different link.
- With active/passive links, failback occurs from the replica to the primary system for the same link. Failback cannot occur from the replica for one link to the primary system for another link.
- With an active/passive link, when a link fails over to the replica, only the HCP tenants and namespaces and default-namespace directories that were read-write on the primary system become read-write on the replica.
- In a complex replication topology that includes only active/passive links in many-to-one and/or chained relationships, the HCP tenants and namespaces and default-namespace directories being replicated in the topology are read-write on at most one HCP system at a time. This is true regardless of the type of activity on the links.
Additional considerations apply to failover and failback in replication topologies that include multiple links.