I use a fresh install of `CDH 5.5.2`. In `Cloudera Manager` I see, that `HDFS` has a critical health issue. I have 1 `NameNode` and 1 `DataNode` in cluster.

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> Under-Replicated Blocks
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> 

[![Under-Replicated Blocks](https://i.stack.imgur.com/Lx2rh.png)](https://i.stack.imgur.com/Lx2rh.png)

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> 578 under replicated blocks in the cluster. 580 total blocks in the
>  cluster. Percentage under replicated blocks: 99.66%. Critical
>  threshold: 40.00%
> 
> 
> 

How should I fix this issue?

UPDATE: `Cloudera Manager(CDH 5.0.2) -> HDFS -> Configuration -> View and Edit -> Service-Wide -> Replication -> Replication Factor (dfs.replication) -> 1` isn't working in this case.