You need to create a temporary copy of a LUN for testing purposes.

You need to make a copy of your data available to additional users without giving them access to the production data.

You want to create a clone of a database for manipulation and projection operations, while preserving the original data in an unaltered form.

You want to access a specific subset of a LUN’s data (a specific logical volume or file system in a volume group, or a specific file or set of files in a file system) and copy it to the original LUN, without restoring the rest of the data in the original LUN. This works on operating systems that support mounting a LUN and a clone of the LUN at the same time. SnapDrive for UNIX supports this with the snap connect command.

You need multiple SAN boot hosts with the same operating system.