HSG80 ACS Solution Software Version 8.7 for Compaq OpenVMS Installation and Configuration Guide

Planning a Subsystem
1–16 HSG80 ACS Solution Software Version 8.7 for Compaq OpenVMS Installation and
Configuration Guide
For example:
In Figure 1–8, restricting the access of unit D101 to host 3, the host named BROWN
can be done by enabling only the connection to host 3. Enter the following commands:
SET D101 DISABLE_ACCESS_PATH=ALL
SET D101 ENABLE_ACCESS_PATH=BROWN1B2
If the storage subsystem has more than one host connection, carefully specify the
access path to avoid providing undesired host connections access to the unit. The
default condition for a unit is that access paths to all host connections are enabled. To
restrict host access to a set of host connections, specify
DISABLE_ACCESS_PATH=ALL for the unit, then specify the set of host connections
that are to have access to the unit.
Enabling the access path to a particular host connection does not override previously
enabled access paths. All access paths previously enabled are still valid; the new host
connection is simply added to the list of connections that can access the unit.
NOTE: The procedure of restricting access by enabling all access paths then disabling selected
paths is not recommended because of the potential data/security breach that occurs when a
new host connection is added.
Restricting Host Access in Multiple-Bus Failover Mode
In multiple-bus mode, the units assigned to any port are visible to all ports. There are
two ways to limit host access in multiple-bus failover mode:
• Enabling the access path of selected host connections
• Setting offsets
Enable the Access Path of Selected Host Connections
Host access can be limited by enabling the access of certain host connections and
disabling the access of others. This is done through the ENABLE_ACCESS_PATH and
DISABLE_ACCESS_PATH switches of the
ADD UNIT (or SET unit) commands. Access path
is a unit switch, meaning it must be specified for each unit. Default access means that
the unit is accessible to all hosts. It is important to remember that at least two paths
between the unit and the host must be enabled in order for multiple-bus failover to
work.