Approaches to Zoning
 
There are many ways to group SAN host and storage nodes for a particular Zoning configuration. Zone membership is primarily based on the need for a host to access a storage port. Hosts rarely need to interact directly with each other and storage ports never initiate SAN traffic by virtue of their nature as targets. Zones can be grouped by array, by host operating system, by application, or by location within the data center. In most cases, none of these methods is recommended for the reasons outlined earlier.
 
The recommended grouping method for Zoning is Single Initiator Zoning (SIZ), sometimes called “Single HBA Zoning.” With SIZ, each zone has only a single HBA and one or more storage ports. If the HBA has both disk and tape storage devices, then you need to create two zones: one zone with the HBA and the disk devices and a second zone with the HBA and the tape devices. SIZ is optimal because it prevents any host-to-host interaction and limits RSCNs to just the zones that need the information within the RSCN.
 
Separating the disk and tape devices into separate zones prevents disk RSCNs from impacting tape devices, which tend to be more sensitive to RSCNs. While this level of Zoning might seem to be more labor-intensive compared to less granular grouping methods, it lays the best foundation for SANs, and will ultimately increase uptime and reduce the time required to troubleshoot problems.BEST PRACTICE: Use single HBA Zoning with separate zones for tape and disk traffic when an HBA is carrying both types of traffic.
 
BEST PRACTICE: Use Single Initiator Zoning with separate zones for tape and disk traffic when an HBA is carrying both types of traffic.

Note: As a best practice for large SAN deployments, it is recommended to have more zones with two-member zones versus a single zone with three or more members. This is not a concern in smaller environments.