Directory Design
The Directory Design tab is disabled for Blob Storage targets, because this storage type does not handle structured data.
This tab functions similarly to the Folder Design tab and supports the use of system and index data in naming of the directories that are being migrated to the target system.
Folder Design should be constructed initially by the Microsoft Azure administrator, and then that same design can be customized here to match your Microsoft Azure organization scheme.
If a folder of the same value already exists, nothing is done.