VERITAS Volume Manager 3.5 Administrator's Guide (September 2004)

Understanding VERITAS Volume Manager
Device Discovery
Chapter 1 9
configured only on the disks in enclosure enc1, the failure of the cable
between the hub and the enclosure would make the entire volume
unavailable.
If required, you can replace the default name that VxVM assigns to an
enclosure with one that is more meaningful to your configuration. See
“Renaming an Enclosure” on page 126 for details.
In High Availability (HA) configurations, redundant-loop access to
storage can be implemented by connecting independent controllers on
the host to separate hubs with independent paths to the enclosures as
shown in Figure 1-4 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.
To take account of fault domains when configuring data redundancy, you
can control how mirrored volumes are laid out across enclosures as
described in “Mirroring across Targets, Controllers or Enclosures” on
page 236.
Figure 1-4 Example HA Configuration Using Multiple Hubs/Switches to
Provide Redundant-Loop Access
c2c1
Host
Fibre Channel
Hubs/Switches
Disk Enclosures
enc0 enc1 enc2