Hi, >From the following list
kafka-topics.sh --describe --bootstrap-server rhes75:9092 --topic md Topic: md TopicId: UfQly87bQPCbVKoH-PQheg PartitionCount: 9 ReplicationFactor: 9 Configs: segment.bytes=1073741824,retention.bytes=1073741824 Topic: md Partition: 0 Leader: 12 Replicas: 12,10,8,2,9,11,1,7,3 Isr: 10,1,9,2,12,7,3,11,8 Topic: md Partition: 1 Leader: 9 Replicas: 9,8,2,12,11,1,7,3,10 Isr: 10,1,9,2,12,7,3,11,8 Topic: md Partition: 2 Leader: 11 Replicas: 11,2,12,9,1,7,3,10,8 Isr: 10,1,9,2,12,7,3,11,8 Topic: md Partition: 3 Leader: 1 Replicas: 1,12,9,11,7,3,10,8,2 Isr: 10,1,9,2,12,7,3,11,8 Topic: md Partition: 4 Leader: 7 Replicas: 7,9,11,1,3,10,8,2,12 Isr: 10,1,9,2,12,7,3,11,8 Topic: md Partition: 5 Leader: 3 Replicas: 3,11,1,7,10,8,2,12,9 Isr: 10,1,9,2,12,7,3,11,8 Topic: md Partition: 6 Leader: 10 Replicas: 10,1,7,3,8,2,12,9,11 Isr: 10,1,9,2,12,7,3,11,8 Topic: md Partition: 7 Leader: 8 Replicas: 8,7,3,10,2,12,9,11,1 Isr: 10,1,9,2,12,7,3,11,8 Topic: md Partition: 8 Leader: 2 Replicas: 2,3,10,8,12,9,11,1,7 Isr: 10,1,9,2,12,7,3,11,8 so for topic md I have 9 Partitions and 9 Replication As for redundancy and prevent data loss I only need 3 replicas (the leader and 2 followers) , so I use the following to reduce the number of replicas to 3 { "version":1, "partitions":[ {"topic":"md","partition":0,"replicas":[12,10,8,2,9,11,1,7,3]}, {"topic":"md","partition":1,"replicas":[9,8,2,12,11,1,7,3,10]}, {"topic":"md","partition":2,"replicas":[11,2,12,9,1,7,3,10,8]} ] } with the following command kafka-reassign-partitions.sh --bootstrap-server rhes75:9092 --reassignment-json-file ./reduce_replication_factor2.json --execute and this is the output Current partition replica assignment {"version":1,"partitions":[{"topic":"md","partition":0,"replicas":[12,10,8,2,9,11,1,7,3],"log_dirs":["any","any","any","any","any","any","any","any","any"]},{"topic":"md","partition":1,"replicas":[9,8,2,12,11,1,7,3,10],"log_dirs":["any","any","any","any","any","any","any","any","any"]},{"topic":"md","partition":2,"replicas":[11,2,12,9,1,7,3,10,8],"log_dirs":["any","any","any","any","any","any","any","any","any"]}]} Save this to use as the --reassignment-json-file option during rollback *Successfully started partition reassignments for md-0,md-1,md-2* It says it is doing it, but nothing is happening! This is the size of Kafka Topic in MB per each per partition remaining: kafka-log-dirs.sh --bootstrap-server rhes75:9092 --topic-list md --describe | grep -oP '(?<=size":)\d+' | awk '{ sum += $1 } END { print sum/1024/1024/9 }' Which comes back with 81.5 MB Will this work as I have stopped the queue but still data there. In short, is downsizing practical? Thanks *Disclaimer:* Use it at your own risk. Any and all responsibility for any loss, damage or destruction of data or any other property which may arise from relying on this email's technical content is explicitly disclaimed. The author will in no case be liable for any monetary damages arising from such loss, damage or destruction.