A storage apparatus is operable as primary in a remote copy pair and
comprises a remote copy component operable to establish a remote copy
relationship between said primary and a secondary; a copy component
operable at the primary to create a copy for download onto a portable
physical storage medium for offline transport to the secondary for
upload; a synchronization component for synchronizing data at said
secondary with data at said primary using an online link in response to a
request for synchronization from the secondary; a metadata component
operable to store a dirty state indicator of a portion of a storage space
at the primary after establishment of the remote copy relationship at the
primary; and the metadata component being operable to limit
synchronization at the secondary to the portion of storage having a dirty
state indicator at the primary.