Managing HDFS Quotas

The Hadoop Distributed File System (HDFS) allows the administrator to set quotas for the number of names used and the amount of space used for individual directories. Name quotas and space quotas operate independently, but the administration and implementation of the two types of quotas are closely parallel.
Name Quotas
The name quota is a hard limit on the number of file and directory names in the tree rooted at that directory. File and directory creations fail if the quota would be exceeded.

Space Quotas
The space quota is a hard limit on the number of bytes used by files in the tree rooted at that directory. Block allocations fail if the quota would not allow a full block to be written.
[hdpsysuser@nn01 ~]$ hdfs dfsadmin -setQuota 1 /userdata/inam

[hdpsysuser@nn01 ~]$ hdfs dfs -put /tmp/mydata/test3.txt /userdata/inam

put: The NameSpace quota (directories and files) of directory /userdata/inam is exceeded: quota=1 file count=3

[hdpsysuser@nn01 ~]$ hdfs dfsadmin -clrQuota /userdata/inam

[hdpsysuser@nn01 ~]$ hdfs dfs -put /tmp/mydata/test3.txt /userdata/inam

[hdpsysuser@nn01 ~]$ hdfs dfsadmin -setSpaceQuota 1m /userdata/inam

[hdpsysuser@nn01 ~]$ hdfs dfs -put /tmp/mydata/Tamm-Sample.txt /userdata/inam

17/05/07 15:36:09 WARN hdfs.DFSClient: DataStreamer Exception

org.apache.hadoop.hdfs.protocol.DSQuotaExceededException: The DiskSpace quota of /userdata/inam is exceeded: quota = 1048576 B = 1 MB but diskspace consumed = 402653256 B = 384.00 MB

[hdpsysuser@nn01 ~]$ hdfs dfsadmin -clrSpaceQuota /userdata/inam

[hdpsysuser@nn01 ~]$ hdfs dfs -put /tmp/mydata/Tamm-Sample.txt /userdata/inam

[hdpsysuser@nn01 ~]$ hdfs dfs -count -q /userdata/inam

           1              -2            none             inf            1            2            2097176 /userdata/inam