Port Allocation; Single Hba - HP A7340A - Surestore FC 1Gb/2Gb Switch 16B User Manual

Port allocation

There is an option to zone based on switch port rather than the WWN of the
device. This provides some security to the fabric, but requires very solid processes
to prevent the incorrect device from being attached to the wrong ports. This form
of zoning should be avoided unless the administration team has very rigidly
enforced processes for port and device allocation in the fabric. It does however
provide some positive features. For instance, when a storage port, server HBA, or
tape drive is replaced, the change of WWN for the new device is of no
consequence. As long as the new device is connected to the original port, it will
continue to have the same access rights. The ports on the edge switches can be
pre-associated to storage ports and control of the fan-in ratio can be established.
With this technique, the administrative team could not overload any one storage
port by associating too many servers with it.

Single HBA

This method of zoning most closely re-creates the original SCSI bus. Each zone
created has only one HBA (initiator) in the zone. Then each of the target devices
that the initiator should access is added to the zone. Typically, a zone would be
created for the HBA, and the disk storage ports would be added. If the HBA
accesses tape devices, a second zone is created with the HBA and associated tape
devices in it. In the case of clustered systems, it may be appropriate to have an
HBA from each of the cluster members included in the zone. This is equivalent to
having a shared SCSI bus between the cluster members. This presumes that the
clustering software provides a methodology to manage access to the shared
devices.
In a large fabric, this does require the creation of possibly hundreds of zones.
However, each zone would contain only a few members. Zone changes would
affect the smallest possible number of devices. The impact of an incorrect zone
change would be minimized. This zoning philosophy is the preferred method.
Zoning Version 3.1.x/4.1.x User Guide
Zoning Concepts and Guidelines
59