Cannot destroy ZFS snapshot: dataset already exists
Solution 1:
This issue has now been answered, courtesy of Cindy Swearingen (cindys) here: http://opensolaris.org/jive/thread.jspa?messageID=484242&tstart=0
Summary: If you do incremental receives, this might be CR 6860996:
A temporary clone is created for an incremental receive and in some cases, is not removed automatically.
1. Determine clone names:
# zdb -d <poolname> | grep %
2. Destroy identified clones:
# zfs destroy <clone-with-%-in-the-name>
It will complain that 'dataset does not exist', but you can check
again(see 1)
3. Destroy snapshot(s) that could not be destroyed previously
Solution 2:
After having upgraded to more recent patch sets, I could delete this snapshot successfully. Clearly was a bug somewhere that Sun squashed.
Solution 3:
Whilst this solution is probably unrelated to the OP's issue, I also had this same cryptic error message when trying to delete a zvol.
In my case, the zvol had been created by an interrupted zfs receive, which was sent using the "-s" resumable feature. The resume token was preventing it from being destroyed.
To fix it, I ran zfs receive -A <pool/zvol> (on FreeBSD 10.3)
Solution 4:
I don't expect this is the issue (I think you get a different error message), but do you have any clones based on that snapshot?