Coordinating establishment of source and target copy relationships on primary and secondary servers

A system for establishing copy relationships for primary storage and secondary storage, comprising:

• a primary server coupled to the primary storage;
• a secondary server coupled to the secondary storage and in communication with the primary server;
• wherein the primary server performs operations, the operations comprising:
• receiving a command to establish a primary copy relationship of primary source data in the primary storage to copy to primary target data in the primary storage and a secondary copy relationship of secondary source data in the secondary storage to copy to secondary target data in the secondary storage;
• determining whether a part of the secondary target data in a secondary pre-existing copy relationship at the secondary storage can be withdrawn from the secondary pre-existing copy relationship;
• in response to determining that the part of the secondary target data in the secondary pre-existing copy relationship can be withdrawn,
• establishing the primary copy relationship for the primary storage;
• and
• establishing, by the secondary server, the secondary copy relationship for the secondary storage.

A method for establishing copy relationships for primary storage and secondary storage, comprising:

• receiving a command to establish a primary copy relationship of primary source data in the primary storage to copy to primary target data in the primary storage and a secondary copy relationship of secondary source data in the secondary storage to copy to secondary target data in the secondary storage;
• determining whether a part of the secondary target data in a secondary pre-existing copy relationship at the secondary storage can be withdrawn from the secondary pre-existing copy relationship;
• in response to determining that the part of the secondary target data in the secondary pre-existing copy relationship can be withdrawn, performing:
• establishing the primary copy relationship for the primary storage;
• and
• establishing the secondary copy relationship for the secondary storage.