Data loss tolerance is a nonfunctional requirement that defines how much message loss is acceptable during broker outages, network partitions, or system crashes. It shapes persistence, acknowledgment, fallback, and operational decisions. section 10.1.4
Classify tolerance according to business impact:
- Critical: accept no message loss; persist events and fully acknowledge them. section 10.1.4
- Important: tolerate occasional loss only when fallback mechanisms exist. section 10.1.4
- Non-critical: use best-effort delivery when loss has minimal business impact. section 10.1.4
Failure-policy decision
A message stream exposed to broker outages should first be classified as critical, important, or non-critical. That classification determines whether the design requires full acknowledgment, fallback handling, or best-effort delivery. section 10.1.4
