Disconnecting external systems and volumes
You can disconnect a single mapped external volume, or all the mapped volumes in an external system. You disconnect all volumes by disconnecting the system itself.
You disconnect a volume or system in order to perform the following operations:
Turn off the power supply of the local or external storage system
Delete an external volume’s mapping
Access a mapped external volume or volumes from the external storage system
When you disconnect a volume or volumes, they stop accepting host I/O, and all data in cache is written to the volumes (data is destaged). Also, the mapping settings are preserved. When the volumes are reconnected, they are assigned the same settings.