How the du command accounts for space usage

When you run the du command to check the disk space usage for a qtree or volume mounted on a UNIX client, the usage value might be higher than the value displayed by a quota report for the qtree or volume.

The output of the du command contains the combined space usage of all the files through the directory tree beginning at the level of the directory where the command is issued. Because the usage value displayed by the du command also includes the data blocks for directories, it is higher than the value displayed by a quota report.

Example of the difference between space usage accounted by the du command and a quota report

The following quota report shows a limit of 10 MB for a qtree q1:

system1>quota report
                                 K-Bytes             Files
Type       ID    Volume    Tree  Used      Limit     Used    Limit   Quota Specifier
----- -------- -------- -------- --------- --------- ------- ------- ---------------
tree    user1      vol1     q1    10485760  10485760       1       - /vol/vol1/q1
...

In the following example, the disk space usage as the output of the du command shows a higher value that exceeds the quota limit:

[user1@lin-sys1 q1]$ du -sh
11M     q1