R12 also features configuration sharing via a sharing script for pushing configuration from a master Nginx Plus instance to peers. This process is used for backups and verifies the validity of the configuration on remote peer. Enhanced caching, meanwhile, is enabled via
Stale-if Error cache extensions. Cache revalidation is done in the background to keep users from being delayed by a round trip to the original server.
To improve health checking, traffic can be delayed to new servers in a load-balancing pool until a health check passes. Servers are added via the API or DNS interfaces, and a slow-start capability enables servers to be gradually introduced to the pool. Nginix also offers greater visibility into application performance, including server response times, error codes for TCP/UPD services, and shared memory zone utilization. These metrics can be viewed via the server's live activity monitoring dashboard, or they can be exported in JSON format into another monitoring tool.
When upgrading to R12, the on-disk cache will be invalid and Nginx Plus automatically refreshes the cache as needed; old cache entries are deleted. Also, connections to upstream servers can be queued if servers are overloaded; the queue directive must be placed after any load-balancing directives. Third-party dynamic modules installed from the Nginx repository will be automatically updated during the upgrade; any third-party modules users built will require manual updates.