We had a similar issue a while ago, and it was HBase Canary on each region server scanning hbase:meta region every few seconds. You can try disabling "HBase Canary" on Cloudera Manager configuration page and restarting the servers.
But if you don't wish to restart for some reason, manually killing Canary processes (org.apache.hadoop.hbase.tool.Canary) will do. Note that we had to kill their parent processes first to prevent respawning. To see which regions are currently being accessed, you might want to check out tools like hbase-region-inspector. https://github.com/kakao/hbase-region-inspector - junegunn
