Described are techniques used in dynamically modifying RDF groups. A system
call is issued by a host computer system to execute a remote system call on a first
data storage system to create, remove, or modify an RDF group between the first
data storage system and another data storage system that is remotely connected
to the first data storage system in an RDF switched environment. As part of executing
the remote system call, data is pushed from the first to the second data storage
systems without having an established link between the data storage systems. Each
data storage system performs processing to make the necessary modifications in
all directors in accordance with the dynamic RDF group. A status indicating success
or failure of the remote system call is returned to the host computer system.
