HSG80 ACS Solution Software V8.6 for IBM AIM Installation and Configuration Guide

1–18 HSG80 ACS Solution Software Version 8.6 for IBM AIX Installation and Configuration Guide
NOTE: The default condition is ENABLE_ACCESS_PATH=ALL. This specifies that access paths
to ALL hosts are enabled. It is recommended that the user restrict host access and that the
access path be carefully specified to avoid providing undesired host connections access to the
unit.
Restricting Host Access in Transparent Failover Mode
Three methods can be used to restrict host access to storage units in transparent failover
mode:
■ Using separate Fibre Channel links (either loop or fabric)
■ Enabling the access path of selected host connections on a shared loop or fabric
■ Setting offsets
NOTE: These techniques also work for a single controller.
Restricting Host Access by Separate Links
In transparent failover mode, host port 1 of controller A and host port 1 of controller B
share a common Fibre Channel link. Host port 2 of controller A and host port 2 of
controller B also share a common Fibre Channel link. If the host 1 link is separate from the
host 2 link, the simplest way to limit host access is to have one host or set of hosts on the
port 1 link, and another host or set of hosts on the port 2 link. Each host can then see only
units assigned to its respective controller port. This separation of host buses is shown in
Figure 1–11. This method applies only if the host 1 link and host 2 link are separate links.
NOTE: Compaq highly recommends that you provide access to only specific connections. This
way, if new connections are added, they will not have automatic access to all units. See the
following section Restricting Host Access by Disabling Access Paths.