When you take a Snapshot copy of a Data ONTAP LUN, the Snapshot copy is initially backed by data in the LUN. After the Snapshot copy is taken, data written to the LUN is available in the active file system.
After you have a Snapshot copy, you can use it to create a LUN clone for temporary use as a prototype for testing data or scripts in applications or databases. Because the LUN clone is backed by the Snapshot copy, you cannot delete the Snapshot copy until you split the clone from it.
To restore the LUN from a Snapshot copy, you can use SnapRestore. However, the restored LUN does not have any updates to the data since the Snapshot copy was taken.
When you create the LUN, space reservation is enabled by default. This means that enough space is reserved so that write operations to the LUNs are guaranteed. The more space that is reserved, the less free space is available. If free space within the volume is below a certain threshold, Snapshot copies cannot be taken.