Empty periodic snapshots show used space

[nelem]

I have hourly periodic snapshots on a couple of different datasets. For one dataset, when there have been no changes, the used value is zero. On another, every snapshot shows 81.4KiB used in every snapshot. I have zfs diff'ed the snapshots with the parent dataset and between each snapshot and there are no changes.

Any suggestions as to how to fix this? I would like to use clearempty.py to remove the snapshots with no differences but this 'spurious' size is preventing it from working.

 

[m0nkey_]

You have atime enabled on the dataset. Even reads will cause the access time to be updated, therefore a snapshot of approx 80K.

 

[nelem]

You have atime enabled on the dataset. Even reads will cause the access time to be updated, therefore a snapshot of approx 80K.

That's it! Thanks, @m0nkey_ I have turned off atime on the root dataset and child datasets inherit the new value (off).