Brocade Fabric OS Administrators Guide (Supporting Fabric OS v7.3.0) - Manual (Page 303)

Considerations for zoning architecture (Continued) TABLE 63
Item Description
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.
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 forward-
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.
If there are no broadcast zones or if a broadcast zone is defined but not enabled, broadcast frames are
not forwarded to any F_Ports. If a broadcast zone is enabled, broadcast frames are delivered only to
Best practices for zoning
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