544 Implementing the IBM Storwize V7000 with IBM Spectrum Virtualize V8.2.1
If 1920 events are occurring, you might need to use a performance monitoring and analysis 
tool, such as the IBM Spectrum Control, to help identify and resolve the problem.
11.7.4   System partnership
To create a partnership, use the following command, depending on the connection type:
/SM590000Use the mkfcpartnership command to establish a one-way MM/GM partnership between 
the local system and a remote system that are linked over an FC (or FCoE) connection.
/SM590000Use the mkippartnership command to establish a one-way MM/GM partnership between 
the local system and a remote system that are linked over an IP connection.
To establish a fully functional MM/GM partnership, you must issue this command on both 
systems. This step is a prerequisite for creating MM/GM relationships between volumes on 
the IBM Spectrum Virtualize systems.
When creating the partnership, you must specify the Link Bandwidth and can specify the 
Background Copy Rate:
/SM590000The Link Bandwidth, expressed in Mbps (megabits per second), is the amount of 
bandwidth that can be used for the FC or IP connection between the systems within the 
partnership. 
/SM590000The Background Copy Rate is the maximum percentage of the Link Bandwidth that can be 
used for background copy operations. The default value is 50%. 
Background copy bandwidth effect on foreground I/O latency
The combination of the Link Bandwidth value and the Background Copy Rate percentage is 
referred to as the Background Copy bandwidth. It must be at least 8 Mbps. For example, if the 
Link Bandwidth is set to 10000 and the Background Copy Rate is set to 20, then the resulting 
Background Copy bandwidth that is used for background operations is 200 Mbps.
The background copy bandwidth determines the rate at which the background copy is 
attempted for MM/GM. The background copy bandwidth can affect foreground I/O latency in 
one of the following ways:
/SM590000The following results can occur if the background copy bandwidth is set too high compared 
to the MM/GM intercluster link capacity: 
– The background copy I/Os can back up on the MM/GM intercluster link.
– There is a delay in t he synchronous auxiliary writes of foreground I/Os.
– The foreground I/O latency increases as perceived by applications.
/SM590000If the background copy bandwidth is set too high for the storage at the primary site, 
background copy read I/Os overload the primary storage and delay foreground I/Os. 
/SM590000If the background copy bandwidth is set too high for the storage at the secondary site, 
background copy writes at the secondary site overload the auxiliary storage, and again 
delay the synchronous secondary writes of foreground I/Os.
To set the background copy bandwidth optimally, ensure that you consider all three resources: 
Primary storage, intercluster link bandwidth, and auxiliary storage. Provision the most 
restrictive of these three resources between the background copy bandwidth and the peak 
foreground I/O workload. 
Perform this provisioning by calculation or by determining experimentally how much 
background copy can be allowed before the foreground I/O latency becomes unacceptable. 
Then, reduce the background copy to accommodate peaks in workload.