The df command reports information about saved space for a file system. The Reduction column reports the amount of data that has been saved either by file system packing or dedupe, or both. For a file system with packing disabled, it represents the saving using the dedupe feature.
For example:
- All columns except Snapshots and
Reduction have the same meaning as a normal file system:
- Size column: The formatted capacity of the file system.
- Used column: The amount (and percentage) of formatted capacity used by live and snapshot data.
- Avail column: The amount of formatted capacity available for further data.
- Reduction column
- This column reports the amount (and percentage) of saved space achieved by either file system packing or dedupe, or both.
- Snapshots column
- This column normally reports the amount (and percentage) of logical space used by snapshots.
- On file systems that do not support dedupe, the logical size of data is equal to the physical space used by that data. However, on file systems that support dedupe, the logical space used by snapshots can exceed the physical used size due to block sharing through Dedupe.
- In some cases, snapshot space usage can even exceed the total formatted capacity of file system size. To avoid confusion, the Snapshots column displays NA for file systems that support dedupe.