IBM DS8000 - Manual (Page 151)

Chapter 7. Copy Services 129
Figure 7-11 z/OS Global Mirror
z/OS Metro/Global Mirror (3-site z/OS Global Mirror and Metro Mirror)
This mirroring capability uses z/OS Global Mirror to mirror primary site data to a location that
is a long distance away and also uses Metro Mirror to mirror primary site data to a location
within the metropolitan area. This enables a z/OS 3-site high availability and disaster recovery
solution for even greater protection from unplanned outages. The z/OS Metro/Global Mirror
function is an optional function. To use it, you must purchase both of the following functions:
Remote Mirror for z/OS (2244 Model RMZ)
Remote Mirror and Copy function (2244 Model RMC) for both the primary and secondary
storage units
2
1
Server write
Write acknowledge
Write
ashynchronously
Primary server
System
Data
Mover
Secondary server
System Data Mover is
managing data consistency