I have a running cluster with 3 live datanodes, with a default HDFS replication factor of 3. I only get 111 total blocks on my datanodes, but I still have 45 blocks “under-replicated” (even if I let the cluster running for some days)
I don’t understand why, because the namenode should automatically handle this replication.
But are these block really under-replicated ?
I’ve seen some threads on the web that indicate that it can be a “display” bug with all Hadoop 0.20 versions (for example, this one : http://stackoverflow.com/questions/7997587/under-replicated-blocks-count-is-inaccurate-buy-why)
Do you agree with that ? Or shoud I always have 0 under replicated blocks.
Many thanks for your help,