Figure 5-5 shows a general Multi-Target PPRC topology where a single primary site is  replicated to two secondary sites. Host I/O is directed to the H1 site and Multi-Target PPRC  mirrors the updates to both H2 and H3. A primary volume can have any combination of two Metro Mirror, Gl obal Copy, or Global  Mirror relationships, with a restriction that a primary volume can be long to only one Global  Mirror session at a time. Note:  A volume can be in only one Global Mirror session. Little extra host response time impact occurs with two relationships c ompared to one  relationship of the same type. Multi-Target PPRC is available in both  open systems and  z Systems environments. For more information, see  IBM DS8870 Multiple Target Peer-to-Pe er Remote Copy ,  REDP-5151. 150  IBM DS8880 Architecture and Implementation Figure 5-5 Basic Multi-Target PPRC configuration Host Server Signal  H2 Cache  Write hit 4 2 Replicate WRITE to H2 2 Replicate WRITE to H3 2 Metro Mirror HyperSwap WRITE g write  completed Cache  Write hit Site 2 or H2 1 3 Cache  2 3 Metro Mirror FCP links H1 Site 1 or H1 3 Write completed in H3 H3 Site 3 or H3 Write hit FCP links 3 Write completed in H2