System Administration Guide: Devices and File Systems

Deleting a UFS Snapshot

When you create a UFS snapshot, you can specify that the backing-store file is unlinked. An unlinked backing-store file is removed after the snapshot is deleted. If you don't specify the -o unlink option when you create a UFS snapshot, you must manually delete the backing-store file.

The backing-store file occupies disk space until the snapshot is deleted, whether you use the -o unlink option to remove the backing-store file or you manually delete the file.