HP XP P9500 Storage - Manual (Page 142)

If no ports are registered in a host group, hosts in the host group can access volumes through ports
connected to the hosts.
Port-level security is a security policy used to permit access by hosts to volumes through ports
registered in host groups and to prohibit access through unregistered ports.
CAUTION: Before applying security, you must confirm which hosts are performing I/O operations
on which volumes in the access groups. If any hosts are performing I/O operations on volumes in
access groups to which the hosts do not belong, you must stop the I/O operations before applying
security. For example, if you were to attempt to apply the security settings shown in the previous
figure, an error would occur and the attempt would fail if host4 and host5 were performing I/O
operations on ldev1. To successfully apply the security settings, you would need to ensure that
host4 and host5 were not performing I/O operations on ldev1.
Prohibiting All Hosts from Accessing Volumes
If you want to prevent all the mainframe hosts from accessing volumes, you must register the volumes
in a pool group. You do not need to register hosts in pool groups. For example, if you register two
142 Protecting volumes from I/O operations