Best practices for Zoning on Brocade switches.
Zoning is a fabric-based service in the Storage Area Networks that groups host and storage nodes that need to communicate. Zoning creates a situation in which nodes can communicate with each other only if they are members of the same zone. Nodes can be members of multiple zones - allowing for a great deal of flexibility when you implement a SAN using Zoning.
Zoning not only prevents a host from unauthorized access of storage assets, but it also stops undesired host-to-host communication and fabric-wide Registered State Change Notification (RSCN) disruptions. RSCNs are managed by the fabric Name Server and notify end devices of events in the fabric, such as a storage node or a switch going offline.
Brocade isolates these notifications to only the zones that require the update, so nodes that are unaffected by the fabric change do not receive the RSCN. This is important for non-disruptive fabric operations, because RSCNs have the potential to disrupt storage traffic. When this disruption was more common, that is, with older Host Bus Adapter (HBA) drivers, RSCNs gained an undeserved negative reputation. However, since that time most HBA vendors have addressed the issues. When nodes are zoned into small, granular groupings, the occurrences of disruptive RSCNs are virtually eliminated.
Zoning is the most common management activity in a SAN. To create a solid foundation for a new SAN, adopt a set of best practices to ensure that the SAN is secure, stable, and easy to manage.
The following recommendations comprise the Zoning best practices that SAN administrators should consider when implementing Zoning:
- Always implement Zoning, even if LUN Masking is being used.
- Always persistently disable all unused ports to increase security and avoid potential problems.
- Use pWWN identification for all Zoning configuration unless special circumstances require D,P identification (for example, FICON).
- Make Zoning aliases and names only as long as required to allow maximum scaling (in very large fabrics of 5000+ ports for Fabric OS 5.2.0+).
- All Zones should use frame-based hardware enforcement.
- Use Single Initiator Zoning with separate zones for tape and disk traffic if an HBA is carrying both types of traffic.
- Implement default zone --noaccess for FOS fabrics.
- Abandon inaccurate Zoning terminology and describe Zoning by enforcement method and identification type.
- Use the free Brocade SAN Health software and the Fabric OS command zone -validate to validate the Zoning configurations.