Compaq StorageWorks HSG60 ACS Solution Software V8.6 for Compaq Tru64 UNIX Installation and Configuration Guide

Planning a Subsystem 1–25
For example:
Figure 1–12 shows a representative multiple-bus failover configuration. Restricting the
access of unit D101 to host BLUE can be done by enabling only the connections to host
BLUE. At least two connections must be enabled for multiple-bus failover to work. For
most operating systems, it is desirable to have all connections to the host enabled. To
enable all connections for host BLUE, enter the following commands:
SET D101 DISABLE_ACCESS_PATH=ALL
SET D101 ENABLE_ACCESS_PATH=BLUE1A1,BLUE1B1,BLUE2A2,BLUE2B2
To enable only two connections for host BLUE (if it is a restriction of the operating
system), select two connections that use different adapters, different switches or hubs, and
different controllers:
SET D101 DISABLE_ACCESS_PATH=ALL
SET D101 ENABLE_ACCESS_PATH=(BLUE1A1,BLUE2B2)
or
SET D101 DISABLE_ACCESS_PATH=ALL
SET D101 ENABLE_ACCESS_PATH=(BLUE1B1,BLUE2A2)
If the storage subsystem has more than one host connection, the access path must be
specified carefully to avoid giving undesirable 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
when the unit is added, then use the SET unit command to 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.
IMPORTANT: The procedure of restricting access by enabling all access paths then disabling
selected paths is particularly 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. However,
depending on the operating system, hosts that have lower offsets may be able to access the
units in the specified range.