[ZFS] diff – what changed between ZFS snapshots

The diff command tells you what files were changed/added/deleted between snapshots.

#list snapshots of a dataset
zfs list -rt snapshot | grep zpool/dataset
zpool/dataset@zfs-auto-snap_monthly-2020-03-01-0552
zpool/dataset@zfs-auto-snap_monthly-2020-04-01-0552
...
#choose two snapshots and use the diff command
zfs diff -FH zpool/dataset@zfs-auto-snap_monthly-2020-03-01-0552 zpool/dataset@zfs-auto-snap_monthly-2020-04-01-0452

The diff command can also show the difference between a snapshot and a current dataset.

zfs diff -FH zpool/dataset@zfs-auto-snap_monthly-2020-03-01-0552 zpool/dataset

The first column indicates the type of change:

-       The path has been removed
+       The path has been created
M       The path has been modified
R       The path has been renamed

The second column indicates the file type, similar to ls. For further information have a look into the zfs man page.

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