There is a long-standing RFE for zfs to be able to describe
what has changed between the snapshots of a dataset.
To provide this capability, we propose a new 'zfs diff'
sub-command. When run with appropriate privilege the
sub-command describes what file system level changes have
occurred between the requested snapshots. A diff between the
current version of the file system and one of its snapshots is
Five types of change are described:
o File/Directory modified
o File/Directory present in older snapshot but not newer
o File/Directory present in newer snapshot but not older
o File/Directory renamed
o File link count changed
zfs diff snapshot snapshot | filesystem
Gives a high level description of the differences between a
snapshot and a descendant dataset. The descendant may either
be a later snapshot of the dataset or the current dataset.
For each file system object that has undergone a change
between the original snapshot and the descendant, the type of
change is described along with the name of the file or
directory. In the case of a rename, both the old and new
names are shown.
The type of change is described with a single character:
+ Indicates the file/directory was added in the later dataset
- Indicates the file/directory was removed in the later dataset
M Indicates the file/directory was modified in the later dataset
R Indicates the file/directory was renamed in the later dataset
If the modification involved a change in the link count of a
file, the change will be expressed as a delta within
parentheses on the modification line. Example outputs are
M /myfiles/link_to_me (+1)
R /myfiles/rename_me -> /myfiles/renamed