Hi, du == *Disk Usage <http://en.wikipedia.org/wiki/Du_%28Unix%29>*. It walks through directory tree and counts the sum size of all files therein. It may not output exact information due to the possibility of unreadable files, hardlinks in directory tree, etc. It will show information about the specific directory requested. Think, *"How much disk space is being used by these files?"*
df == *Disk Free <http://en.wikipedia.org/wiki/Df_%28Unix%29>*. Looks at disk used blocks directly in filesystem metadata. Because of this it returns much faster that du but can only show info about the entire disk/partition. Think, *"How much free disk space do I have?"* *You can go through the link http://linuxshellaccount.blogspot.in/2008/12/why-du-and-df-display-different-values.html <http://linuxshellaccount.blogspot.in/2008/12/why-du-and-df-display-different-values.html>* On Wed, Sep 24, 2014 at 9:51 PM, Tang <[email protected]> wrote: > hi, > > see the du and df command output below. > > [hadoop@master-26161 hadoop]$ /opt/hadoop-2.4.1/bin/hdfs dfs -du -h / > 14/09/25 01:35:03 WARN util.NativeCodeLoader: Unable to load native-hadoop > library for your platform... using builtin-java classes where applicable > 91.9 G /hbase > 492.7 M /var > 390.9 M /tmp > 4.3 M /user > > [hadoop@master-26161 hadoop]$ /opt/hadoop-2.4.1/bin/hdfs dfs -df -h > 14/09/25 01:41:58 WARN util.NativeCodeLoader: Unable to load native-hadoop > library for your platform... using builtin-java classes where applicable > Filesystem Size Used Available Use% > hdfs://master-26151:9000 1.3 T 642.8 G 711.0 G 47% > > you can see "du" say there are 93G data under "/", but "df" says we used > 642.8G. we set replica facotr is 3. > using 93*3=279G would make sense. > so my question: who used other disks? how to clean them? > > Thanks. > Tang > > -- Thanks and Regards, VIVEK KOUL
