Administrator Guide

Fabric OS Administrator’s Guide 343
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Broadcast zones
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Zoning can be implemented and administered from any switch in the fabric, although it is
recommended that you use a switch running the latest Fabric OS version.
The zone configuration is managed on a fabric basis. When a change in the configuration is saved,
enabled, or disabled according to the transactional model, it is automatically (by closing the
transaction) distributed to all switches in the fabric, preventing a single point of failure for zone
information.
NOTE
Zoning commands make changes that affect the entire fabric. When executing fabric-level
configuration tasks, allow time for the changes to propagate across the fabric before executing any
subsequent commands. For a large fabric, you should wait several minutes between commands.
Best practices for zoning
The following are recommendations for using zoning:
• Always zone using the switch with the latest Fabric OS release level.
Switches with earlier Fabric OS versions do not have the capability to view all the functionality
that a newer Fabric OS version provides, as functionality is backwards-compatible but not
forwards-compatible.
• Zone using the core switch versus an edge switch.
• Zone using a Backbone rather than a switch.
A Backbone has more resources to handle zoning changes and implementations.
Broadcast zones
Fibre Channel allows sending broadcast frames to all Nx_Ports if the frame is sent to a broadcast
well-known address (FFFFFF); however, many target devices and HBAs cannot handle broadcast
frames. To control which devices receive broadcast frames, you can create a special zone, called a
broadcast zone, that restricts broadcast packets to only those devices that are members of the
broadcast zone.
Effect of changes in a
production fabric
Zone changes in a production fabric can result in a disruption of I/O under conditions
when an RSCN is issued because of the zone change and the HBA is unable to process the
RSCN fast enough. Although RSCNs are a normal part of a functioning SAN, the pause in
I/O might not be acceptable. For these reasons, you should perform zone changes only
when the resulting behavior is predictable and acceptable. Ensuring that the HBA drivers
are current can shorten the response time in relation to the RSCN.
Testing Before implementing a new zone, you should run the Zone Analyzer from Web Tools to
isolate any possible problems. This is especially useful as fabrics increase in size.
Confirming operation After changing or enabling a zone configuration, you should confirm that the nodes and
storage can identify and access one another. Depending on the platform, you might need
to reboot one or more nodes in the fabric with the new changes.
TABLE 63 Considerations for zoning architecture (Continued)
Item Description