ZFS: Which files are lost when a snaphot is destroyed?

[fillg1]

Hi folks
I am looking for a way to determine which files are affected or lost when a specific ZFS snaphot is deleted / destroyed. So this must be these files which are only referenced by this snapshot.
Any ideas ?

 

[jgreco]

diff?

 

[fillg1]

diff with what?
In my understanding, diff shows the difference between two snapshots but I want to know which files are referenced by a specific snapshot only.

 

[jgreco]

diff with what?
In my understanding, diff shows the difference between two snapshots but I want to know which files are referenced by a specific snapshot only.

diff against the immediately preceding and immediately following snapshots, in succession, then, I guess. Possibly with some grep thrown in to straighten it all out.

 

[fracai]

specifically, the following will print out the difference between the current state and the given snapshot.

Code:

zfs diff <dataset@snapshot>

You can provide a second snapshot to compare two snapshots

 

[Osiris]

When you create a snapshot, zero data is written. Only a timestamp is noted down.
Everything you do on the volume/dataset (or previous snapshot) since that snapshot datetime is saved in that snapshot and the base volume/dataset (or previous snapshot) remains untouched.
When you destroy it, you 'lose' all changes made since snapshot time, being the diff.

If you rollback to a specific snapshot, all snapshots made after that one are then obviously destroyed.
Dunno if it's possible via the gui to rollback to anything besides the last snapshot though.