Using the admin api within rpk
for t in `rpk topic list | awk '$1 !~/NAME/{print $1}'`; do rpk topic describe-storage $t | awk '$1~/NAME/{name = $2} $3~/[0-9]+/{sum += $3} END{print name, sum}'; done
Using grafana & public metrics:
sum by(redpanda_topic)(max by(redpanda_topic, redpanda_partition)(rate(redpanda_kafka_max_offset{redpanda_namespace="kafka",redpanda_id="cmnusu3qaeg64ledkssg"}[5m])))
and/or
sum by(redpanda_topic)(max by(redpanda_topic, redpanda_partition)(rate(redpanda_kafka_request_bytes_total{redpanda_namespace="kafka",redpanda_id="cmnusu3qaeg64ledkssg"}[5m])))
All of the above provided courtesy of James Flather. Thanks James!