When you disconnect external storage systems, and then power off the local storage system, you cannot access the external volume from the local storage system if you power on the external storage system again. To access the external storage system, you must run the Reconnect External Storage Systems command. This procedure checks whether the defined configuration information of each external volume mapped as a local storage volume matches the status of the external volume. If the external volume can be used as a mapped volume, I/O operations to the external volume are accepted, and the volume can be used again.
When you run the Disconnect External Storage Volumes or Disconnect External Volumes command, and all data stored in the cache memory is written to the external volumes, the external volume status changes to Disconnect.