Global Mirror for ESS combines PPRC-Extended Distance pairs (PPRC-XD) with FlashCopy® consistency groups to provide true backup at a secondary site. This is accomplished through the addition of a master session in the hardware configuration. This master session controls all updates to the secondaries of the PPRC-XD pairs and, at the secondary site, the creation of consistent copies (using FlashCopy), at user specified intervals. Global Mirror for ESS requires FCP connection.
For additional information about Global Mirror, refer to Planning for Global Mirror.