Currently my production cluster which is running cdh3u4 has shown
Number of Under-Replicated Blocks around 1k blocks.
Even though we have balancer run every night somehow the number of
under replicate is never go down at all.
The question is how HDFS handles under-replication blocks.
- will namenode takes care when file that has under-replicated blocks
is being used ?
- we need to bump up setrep to kind of trigger the number of replication block ?