HSG80 ACS Solution Software Version 8.7 for Compaq Tru64 UNIX Installation and Configuration Guide

Planning a Subsystem
1–23HSG80 ACS Solution Software Version 8.7 for Compaq Tru64 UNIX Installation and
Configuration Guide
1–23
Restricting Host Access by Disabling Access Paths
If more than one host is on a link (that is, attached to the same port), 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. The access
path is a unit switch, meaning it must be specified for each unit. Default access
enables the unit to be accessible to all hosts.
For example:
In Figure 1–14, 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 by Offsets
Offsets establish the start of the range of units that a host connection can access.
For example:
In Figure 1–13, assume both host connections on port 2 (connections BLACK1B2 and
BROWN1B2) initially have the default port 2 offset of 100. Setting the offset of
connection BROWN1B2 to 120 will present unit D120 to host BROWN as LUN 0.
SET BROWN1B2 UNIT_OFFSET=120