Compaction_throughtput_per_mb is 0 in cassandra.yaml. Is setting it in nodetool going to provide any increase?
From: Durity, Sean R via user <user@cassandra.apache.org> Sent: Thursday, February 16, 2023 4:20 PM To: user@cassandra.apache.org Subject: RE: Cleanup EXTERNAL Clean-up is constrained/throttled by compactionthroughput. If your system can handle it, you can increase that throughput (nodetool setcompactionthroughput) for the clean-up in order to reduce the total time. It is a node-isolated operation, not cluster-involved. I often run clean up on all nodes in a DC at the same time. Think of it as compaction and consider your cluster performance/workload/timelines accordingly. Sean R. Durity From: manish khandelwal <manishkhandelwa...@gmail.com<mailto:manishkhandelwa...@gmail.com>> Sent: Thursday, February 16, 2023 5:05 AM To: user@cassandra.apache.org<mailto:user@cassandra.apache.org> Subject: [EXTERNAL] Re: Cleanup There is no advantage of running cleanup if no new nodes are introduced. So cleanup time should remain same when adding new nodes. Cleanup is a local to node so network bandwidth should have no effect on reducing cleanup time. Dont ignore cleanup There is no advantage of running cleanup if no new nodes are introduced. So cleanup time should remain same when adding new nodes. Cleanup is a local to node so network bandwidth should have no effect on reducing cleanup time. Dont ignore cleanup as it can cause you disks occupied without any use. You should plan to run cleanup in a lean period (low traffic). Also you can use suboptions of keyspace and table names to plan it such a way that I/O pressure is not much. Regards Manish On Thu, Feb 16, 2023 at 3:12 PM Marc Hoppins <marc.hopp...@eset.com<mailto:marc.hopp...@eset.com>> wrote: Hulloa all, I read a thing re. adding new nodes where the recommendation was to run cleanup on the nodes after adding a new node to remove redundant token ranges. I timed this way back when we only had ~20G of data per node and it took approx. 5 mins per node. After adding a node on Tuesday, I figured I'd run cleanup. Per node, it is taking 6+ hours now as we have 2-2.5T per node. Should we be running cleanup regularly regardless of whether or not new nodes have been added? Would it reduce cleanup times for when we do add new nodes? If we double the network bandwidth can we effectively reduce this lengthy cleanup? Maybe just ignore cleanup entirely? I appreciate that cleanup will increase the load but running cleanup on one node at a time seems impractical. How many simultaneous nodes (per rack) should we limit cleanup to? More experienced suggestions would be most appreciated. Marc INTERNAL USE
