Hi,  Unconfigured space is the free space in your symmetrix. A new device will be created  by symmetrix from the free space available in your symmetrix and migration will be performed to this target device when you are using the option: migrating to unconfigured space. However, in case of configured, you can select any other symmetrix device that was created by you as a target of migration.  You can find the detailed explaination in Document available @ [URL]  Thanks Amita Wasson
Hi,  What is configured and unconfigured space used in virtual lun migration? I know that in configured space after migration the primary device will be intact but in case of unconfigured space the primary dev will be deleted once migration is over.  Thanks, Shailender
Virtual Lun migration