Have a look at the below two parameters hbase.client.max.perregion.tasks The maximum number of concurrent connections the client will maintain to a single Region. That is, if there is already hbase.client.max.perregion.tasks writes in progress for this region, new puts won't be sent to this region until some writes finishes. hbase.zookeeper.property.maxClientCnxns - Number of concurrent connections which can be made to a single member of ZK ensemble from a single client and this value should match the value in zoo.cfg. This need to be adjusted taking into consideration the expected number of HBase client connections. ... View more