@aengineer    Also noticed from one comment in HDFS-8789 that " balancer doesn't support anything other than the default placement policy (BlockPlacementPolicyDefault). "   HDFS-14053 says ability for NN to re-replicate blocks based on policy change is fixed in hadoop 3.3.0 [not sure if it's hadoop version or not, though NN version doesn't make sense], while HDFS-14637 supports above statement until UD get enable.  ... View more

@aengineer    HDFS-14637 and HDFS-8789 appear to contradict each other as HDFS-14637 says that after changing the network topology or placement policy on a cluster and restarting the namenode, the namenode will scan all blocks on the cluster at startup, and check if they meet the current placement policy. If they do not, they are added to the replication queue and the namenode will arrange for them to be replicated to ensure the placement policy is used.    It would be good to get some clarity on this.   ... View more

@aengineer In continuation of Smarak's concern, do we have any further info on this?   JIRA HDFS-8789 is still in unresolved state, so looks change in block placement policy is still not applicable to existing blocks.   Any thoughts?   ... View more

Will it be possible to create namespace on the custom hdfs path ? ... View more