Merge branch 'main' into dev

server/jetstream_cluster.go

@@ -6631,6 +6631,14 @@ func (mset *stream) processClusteredInboundMsg(subject, reply string, hdr, msg [
 	if err != nil && mset.clseq > 0 {
 		mset.clseq--
 	}
+
+	// Check to see if we are being overrun.
+	// TODO(dlc) - Make this a limit where we drop messages to protect ourselves, but allow to be configured.
+	const warnThreshold = 10_000
+	if mset.clseq-lseq > warnThreshold {
+		lerr := fmt.Errorf("JetStream stream '%s > %s' has high message lag", jsa.acc().Name, mset.cfg.Name)
+		s.RateLimitWarnf(lerr.Error())
+	}
 	mset.clMu.Unlock()
 
 	if err != nil {