Obtaining additional data storage from another data storage system

Data storage systems for storing data, comprising:

• a local data storage system comprising a local computer-implemented storage control and data storage;
• a main data storage system comprising a main computer-implemented storage control and data storage, and a user interface, said main storage control in communication with said main computer-implemented storage control,
• said main storage control, in response to a request to increase data storage from said user interface, determining whether said main data storage is out of space;
• if said main data storage is out of space, said main storage control sending a command to said local storage control to create data space in local data storage, said data space created by said local storage control associated with said main storage control;
• and
• in response to said local storage control creating data space in said local data storage and notifying said main storage control, said main storage control updating its metadata with respect to said data space.

A computer program product for storing data with data storage systems comprising a main computer-implemented storage control and data storage, and a user interface, and a local computer-implemented storage control and data storage, said main storage control in communication with said local computer-implemented storage control, said computer program product comprising computer-usable storage medium having non-transient computer-usable program code embodied therein, said computer-usable program code comprising:

• computer-usable program code for said main storage control to, in response to a request to increase data storage from said user interface, determine whether said main data storage is out of space;
• computer-usable program code for said main storage control to, if said main data storage is out of space, send a command to said local storage control to create data space in local data storage, said data space created by said local storage control associated with said main storage control;
• and
• computer-usable program code for said main storage control to, in response to said local storage control creating data space in said local data storage and notifying said main storage control, update its metadata with respect to said data space.