How to set an HDFS quota

HDFS quotas stop a directory tree from consuming more namespace entries or replicated storage than planned. A quota change should start with current usage so the new limit does not immediately block active writers.

Name quotas count files and directories. Space quotas count consumed replicated bytes, so a 10 GB file with replication factor 3 consumes 30 GB of space quota.

Quota commands are administrative HDFS operations. Use them on HDFS directories, then check the quota report with hdfs dfs -count -q before handing the path back to users.

Steps to set an HDFS directory quota:

Check current quota and usage for the directory.

$ hdfs dfs -count -q -h /data/projects
       QUOTA REM_QUOTA     SPACE_QUOTA REM_SPACE_QUOTA DIR_COUNT FILE_COUNT CONTENT_SIZE PATHNAME
        none       inf          none           inf        12        112     68.4 G /data/projects

Set a namespace quota for file and directory names.
```
$ hdfs dfsadmin -setQuota 5000 /data/projects
```

Set a replicated space quota.

$ hdfs dfsadmin -setSpaceQuota 2t /data/projects

Verify both quotas.

$ hdfs dfs -count -q -h /data/projects
       QUOTA REM_QUOTA     SPACE_QUOTA REM_SPACE_QUOTA DIR_COUNT FILE_COUNT CONTENT_SIZE PATHNAME
        5000      4876           2 T           1.8 T        12        112     68.4 G /data/projects

Clear the quotas when the directory should return to unlimited usage.
```
$ hdfs dfsadmin -clrQuota /data/projects
```
Run hdfs dfsadmin -clrSpaceQuota /data/projects separately when the space quota must also be removed.