Chapter 3. Planning 51
The hardware compatible with V8.2.1 supports 8 Gbps and 16 Gbps FC fabric, depending on 
the hardware platform and on the switch to which the Storwize V7000 is connected. In an 
environment where you have a fabric with multiple-speed switches, the preferred practice is to 
connect the Storwize V7000 and back-end storage systems to the switch operating at the 
highest speed.
You can use the lsfabric command to generate a report that displays the connectivity 
between nodes and other controllers and hosts. This report is helpful for diagnosing SAN 
problems.
Storwize V7000 control enclosure contains a pair of nodes (I/O Groups). Odd number of 
nodes in a cluster is a valid configuration only if a node fails or is removed from the 
configuration. In such case, the remaining node operates in a degraded mode.
For clustered systems avoid, if possible, communication between nodes that route across 
ISLs. Connect all nodes to the same Fibre Channel or FCF switches.
Direct connection of the system Fibre Channel ports without the use of a Fibre Channel 
switch is supported. Such direct connections between the system nodes might be useful in 
small configurations where there is no Fibre Channel switch. It can also be used to connect 
nodes in the same I/O group to provide a dedicated connection for mirroring the fast write 
cache data. 
No more than three ISL hops are permitted among nodes that are in the same system though 
in different I/O groups. If your configuration requires more than three ISL hops for nodes that 
are in the same system but in different I/O groups, contact your support center.
Avoid ISL on the path between nodes and back-end storage. If possible, connect all storage 
systems to the same Fibre Channel or FCF switches as the nodes. One ISL hop between the 
nodes and the storage systems is permitted. If your configuration requires more than one ISL, 
contact your support center.
In larger configurations, it is common to have ISLs between host systems and the nodes.
To verify the supported connection speed for FC links to the Storwize V7000, use the hIBM 
System Storage Interoperation Center (SSIC) website.
For more information about the configuration of Enhanced Stretched Cluster or HyperSwap 
setup, see IBM System Storage SAN Volume Controller and Storwize V7000 Best Practices 
and Performance Guidelines, SG24-7521.
3.6.2  Zoning
In Storwize V7000 deployments, the SAN fabric must have two distinct zone classes:
/SM590000Host zones: Allows communication between Storwize V7000Storwize V7000 and hosts.
/SM590000Storage zone: Allows communication between Storwize V7000 and back-end storage.
In clustered configurations, a third zone is required that allows communication between 
storage system nodes (intra-cluster traffic).