Technical data

Switch zoning controls access at the storage system level, whereas SSP
controls access at the storage unit level.
The following configurations require zoning or selective storage presentation:
• When you have a TruCluster Server cluster in a storage array network
(SAN) with other stand-alone systems (UNIX or non-UNIX), or other
clusters.
• Any time you have Windows NT or Windows 2000 in the same SAN
with Tru64 UNIX. (Windows NT or Windows 2000 must be in a separate
switch zone.)
• The SAN configuration has more than 64 connections to an RA8000,
ESA12000, MA6000, MA8000, or EMA12000.
The use of selective storage presentation is the preferred way to control
access to storage (so zoning is not required).
6.5.2 Types of Zoning
There are two types of zoning, soft and hard:
• Soft zoning is a software implementation that is based on the Simple
Name Server (SNS) enforcing a zone. Zones are defined by either the
node or port World Wide Names (WWN), or the domain and port numbers
in the form of D,P, where D is the domain and P is the physical port
number on the switch.
A host system requests a list of all adapters and storage controllers that
are connected to the fabric. The name service provides a list of all ports
that are in the same zone or zones as the requesting host bus adapter.
Soft zoning only works if all hosts honor it; it does not work if a host is
not programmed to allow for soft zoning. For instance, if a host tries to
access a controller that is outside the zone, the switch does not prevent
the access.
Tru64 UNIX honors soft zoning and does not attempt to access devices
outside the zone.
If you have used the WWN to define the zone and replace a KGPSA host
bus adapter, you must modify the zone configuration and SSP because
the node World Wide Name has changed.
• With hard zoning, zones are enforced at the physical level across
all fabric switches by hardware blocking of Fibre Channel frames.
Hardware zone definitions are in the form of D,P, where D is the domain
and P is the physical port number on the switch. An example might
be 1,2 for switch 1, port 2.
Using Fibre Channel Storage 6–19