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- The relational database COmanage Registry uses to persist state must itself be deployed in a HA configuration.
- User PHP sessions must be consistent across the HA configuration (nodes) by either using session affinity (sticky sessions) or properly replicating sessions. Two commons approaches are to use memcacheduse Redis or memcached (not withstanding issues with memcached around its ability to recover from node failure). Writing sessions to a relational database that is itself configured for HA is also a common approach though for performance reasons it does not scale as well horizontally.
- Deployers must take into account any HA needs of the federated identity authentication protocol.