Prevent Cloud Sync Tasks from overflowing /mnt
Configuring a cloud sync task has the potential to fill the /mnt directory, therefore disallowing the ability to import your zpools.
/mnt/tank. Create a PULL cloud sync, run it. It should run OK.
/mnt/tank. There should be no directory
/mnt/tank. Run cloud sync. It should say "directory does not exist"
mkdir /mnt/tank (but do not create pool). Run cloud sync. It should say "directory must reside within volume mount point"