Multi-Raft – Boost up write performance for Apache Hadoop-Ozone

published 24.06.2020 18:24

by Guest Author from blog.cloudera.com

For example, with 10 nodes, Ozone cluster would be deployed as 1 master and 9 DataNodes, which leads to 3 three-replica pipelines.

As a result, Ozone’s writing performance has a lot to do with how good pipelines are balancing the writing load onto disks on DataNodes.

Ozone wraps a Raft group made up of datanodes (= replication factor, default is 3) as a Ratis pipeline.

We observed that Ozone with a singular Ratis pipeline per datanode was not able to saturate the disk bandwidth resulting in some variability in write latency.

Adding DataNode 4 into a 3-DataNode multi-Raft cluster can make SCM create (4-1) = 3 more pipelines and every DataNode could join 3 pipelines, letting alone single-Raft can only leave the DN4 as a backup.