522 Implementing the IBM Storwize V7000 with IBM Spectrum Virtualize V8.2.1
Figure 11-88   Write on volume in Metro Mirror relationship
However, this process also means that the application is exposed to the latency and 
bandwidth limitations (if any) of the communication link between the master and auxiliary 
volumes. This process might lead to unacceptable application performance, particularly when 
placed under peak load. Therefore, the use of traditional Fibre Channel Metro Mirror has 
distance limitations that are based on your performance requirements. IBM Spectrum 
Virtualize does not support more than 300 km (186.4 miles).
11.6.7  Metro Mirror features
The IBM Spectrum Virtualize Metro Mirror function supports the following features: 
/SM590000Synchronous remote copy of volumes that are dispersed over metropolitan distances.
/SM590000The Metro Mirror relationships between volume pairs, with each volume in a pair that is 
managed by a Storwize V7000 system or IBM SAN Volume Controller system (requires 
V6.3.0 or later).
/SM590000Supports intracluster Metro Mirror where both volumes belong to the same system (and 
I/O Group).
/SM590000IBM Spectrum Virtualize supports intercluster Metro Mirror where each volume belongs to 
a separate system. You can configure a specific system for partnership with another 
system. All intercluster Metro Mirror processing occurs between two IBM Spectrum 
Virtualize systems that are configured in a partnership. 
/SM590000Intercluster and intracluster Metro Mirror can be used concurrently.
/SM590000IBM Spectrum Virtualize does not require that a control network or fabric is installed to 
manage Metro Mirror. For intercluster Metro Mirror, the system maintains a control link 
between two systems. This control link is used to control the state and coordinate updates 
at either end. The control link is implemented on top of the same FC fabric connection that 
the system uses for Metro Mirror I/O.
/SM590000IBM Spectrum Virtualize implements a configuration model that maintains the Metro Mirror 
configuration and state through major events, such as failover, recovery, and 
resynchronization, to minimize user configuration action through these events.