What is the recommended zoning method when designing fabrics for stand-alone and clustered environments?

Zoning by operating system
Zoning by operating system is the minimal required zoning method. This method allows multiple HBAs with the same operating system to be grouped with the accessed storage ports. Zoning by operating system prevents the interaction of HBAs with incompatible operating systems. This method limits the number of zones in a fabric. A large zone can be divided into multiple zones within the operating system type. Zoning by operating system type limits disruptions and the number of fabric change notifications. Certain situations require zoning by HBA, for example, configuring server access to multiple storage types.
Zoning by HBA ( or Single initiator)
For zoning by HBA, each zone has only one HBA (initiator); each of the target devices is added to the zone.
Typically, a zone is created for the HBA and the disk storage ports are added. If the HBA also accesses tape devices, HP recommends that a second zone be created for the HBA and associated tape devices. For zoning requirements with different HBA models on the same server. This zoning philosophy is the preferred method for both standalone and clustered systems; zoning by single HBA requires the creation of numerous zones; Each containing only a few members. Zone changes affect a small number of devices, minimizing the effect of an incorrect zone change.
Zoning by application
Zoning by application configures multiple, sometimes incompatible, operating systems into the same zones.
This method allows the potential for disruptions among servers, such as a web server disrupting a data warehouse server. A zone with a large number of members is susceptible to more administrative errors, such as distribution of RSCNs to a larger group than necessary. Zoning by port allocation Avoid zoning by port allocation unless you have strictly enforced processes for port and device allocation in the fabric. There is no consequence for the change of WWN when a storage port, server HBA, or tape drive is replaced. If the new device connects to the original port, it continues to have the same access rights. You can preassociate switch ports with storage ports, and therefore control the server-to-storage ratio. This technique prevents overloading of a storage port by allowing you to limit the number of servers that are allowed access.