3.1. Verify HDFS filesystem health

Analyze if the filesystem is healthy.

Run the fsck command on namenode as $HDFS_USER:

hdfs fsck / -files -blocks -locations > dfs-new-fsck-1.log

Run hdfs namespace and report.
- List directories.
```
hdfs dfs -lsr / > dfs-new-lsr-1.log
```
- Run report command to create a list of DataNodes in the cluster.
```
hdfs dfsadmin -report > dfs-new-report-1.log
```
Compare the namespace report before the upgrade and after the upgrade. Verify that user files exist after upgrade.
```
dfs-old-fsck-1.log < -- > dfs-new-fsck-1.log
dfs-old-lsr-1.log < -- > dfs-new-lsr-1.log
```
Note
You must do this comparison manually to catch all errors.
From the Namenode WebUI, see if all DataNodes are up and running.
```
http://<namenode>:50070
```

	Note
You must do this comparison manually to catch all errors.