HP StorageWorks MSA 2.8 SAN Switch - Manual (Page 57)

Zoning Concepts and Guidelines
57 Zoning Version 3.1.x/4.1.x User Guide
Zoning Implementations
Zoning can be enabled on the host, in the switch fabric, and in most storage units.
Storage units typically implement LUN based zoning, commonly referred to as
LUN masking. Fabric switches will implement nameserver-based zoning where
the zone members are identified by WWN or port location in the fabric.
Host-based zoning can implement WWN or LUN masking.
Host-Based Zoning
Host-based zoning requires the host configuration to be correct in order to avoid
zoning conflicts. This provides a greater opportunity for administrative errors to
allow conflicting access to targets. The zoning interface varies from host operating
systems, even among different HBA vendors. This increases the opportunity for
administrative errors to occur. If a host is not configured with the zoning software,
it can access all devices in the fabric resulting in the possibility of data corruption.
Storage-Based Zoning
This form of zoning is usually referred to as LUN masking. Its basic function is to
limit access to the LUNs on the storage port to specific WWN of the server HBA.
This form of zoning is needed in most SANs. It functions during the probe portion
of the SCSI initialization. The server will probe the storage port for a list of
available LUNs and their properties. The storage system will compare the WWN
of the requesting HBA to the defined zone list. It will then return the LUNs that
are assigned to the WWN. Any other LUNs on that storage port will not be made
available to the server.
Fabric-Based Zoning
This is commonly referred to as nameserver based or soft zoning. With HP
switches there may also be additional hardware enforcement of the zone; refer to
Hardware-Enforced Zoning in an HP Fabric on page 65. When a device makes a
query to the fabric nameserver, the nameserver determines which zones the device
belongs to. It then returns to the requesting device information on all members of
the zones that are present in the fabric. Devices in the zone are identified by World
Wide Node Name, World Wide Port Name, or Domain/Port of the switch the
device is connected to.