Veritas Volume Manager 5.0.1 Administrator's Guide, HP-UX 11i v3, First Edition, November 2009

Figure 1-4 shows a High Availability (HA) configuration where redundant-loop
access to storage is implemented by connecting independent controllers on the
host to separate hubs with independent paths to the enclosures.
Figure 1-4
Example HA configuration using multiple hubs or switches to provide
redundant loop access
enc0 enc2
Host
Fibre Channel hubs
or switches
Disk enclosures
c1 c2
enc1
Such a configuration protects against the failure of one of the host controllers
(c1 and c2), or of the cable between the host and one of the hubs. In this example,
each disk is known by the same name to VxVM for all of the paths over which it
can be accessed. For example, the disk device enc0_0 represents a single disk for
which two different paths are known to the operating system, such as c1t99d0
and c2t99d0.
Note: The native multipathing feature of HP-UX 11i v3 similarly maps the various
physical paths to a disk, and presents these as a single persistent device with a
name of the form disk##. However, this mechanism is independent of that used
by VxVM.
For more information on administering native multipathing with Base-VxVM and
VxVM-Full, see the Veritas Volume Manager Release Notes.
Such a configuration protects against the failure of one of the host controllers
(c1 and c2), or of the cable between the host and one of the hubs. In this example,
Understanding Veritas Volume Manager
How VxVM handles storage management
28