Deployment modes

AVEVA PI System Connector 3 (PSC3) supports two deployment modes that influence how and when caching is used. The selected deployment determines whether data is cached immediately to disk or primarily buffered in memory during normal operation.

Connector and Broker on separate machines

When the connector and broker are deployed on separate machines, data is transmitted from the connector to the broker over AMQP/TLS. In this configuration, the connector acts as the primary caching node.

If communication with the broker is interrupted, data is immediately written to disk to prevent data loss. Cached data is retained on the connector until connectivity is restored and the broker can resume accepting messages.

Connector and Broker in the same process

When the connector and broker are deployed within the same process, data is passed through an in-memory buffer rather than sent over the network. This configuration minimizes the need for immediate disk caching during brief disruptions.

Additionally, data is transmitted to the PI Buffer Subsystem, removing the necessity for caching on the connector side if the connection is lost.

Disk-based caching is only activated when specific thresholds are exceeded to relieve memory pressure. This approach maximizes throughput during normal operation while still providing resilience if the downstream destination cannot keep pace with incoming data.