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4.
To configure the VERITAS vxdmp driver to manage the HP 3PAR Storage System server paths
for path failure management and dynamic load balancing, register the storage server as a
generic JBOD device using the following case-sensitive VERITAS command:
# vxddladm addjbod vid-3PARdata
5.
To confirm the VERITAS vxdmp driver has registered the HP 3PAR Storage System as a generic
JBOD device, issue the following VERITAS command:
# vxddladm listjbod
VID
PID
======================================================================
3PARdata
ALL PIDs
6.
PVLinks, a component of Logical Volume Manager (LVM), can be used with storage server
VVs that are exported on multiple paths to the host server to provide path failure management.
PVLinks is an alternate pathing scheme where a primary and one or more alternate paths are
defined for a device. The primary path is used until it fails, which causes one of the alternate
paths to be used until the primary path is restored. In order for path failover with PVLinks to
work, host I/O must be pointed at the LVM Logical Volume device, not at the raw or block
special files in /dev/rdskand /dev/dsk.
WARNING!
Because HP-UX sees every path to a device (i.e., a single storage server VLUN)
as a different device (e.g., cxt0d0 and cyt0d0), the potential to overwrite data on a LUN
exists if I/O is performed directly to the /dev/dsk/ or /dev/rdsk/ special files. The PVLinks
feature is part of LVM volume management. Refer to HP LVM documentation (available at
http://docs.hp.com) for information on using PVLinks. One such reference is the following HP
document: Managing Systems and Workgroups: A Guide for HP-UX System Administrators
HP, 9000, Computers Edition 5Manufacturing Part Number: B2355-90742 Chapter 6:
Administering a System: Managing Disks and Files Section: Setting Up Alternate Links to a
Physical Volume.
Alternate links (paths) to a volume are defined at the volume group level using the vgcreate
command or by using the SAM GUI.
# sam > Disk and File systems > Volume Groups & Logical Volumes
The order of failover paths specified during volume creation is important, as the failover priority
will be considered in the same order as used when the volume was created. For example:
# vgcreate <volume name> <path1> <path2> <path3>...<pathn>
The failover path for the primary active path will be increased by 1 up to path n.
NOTE:
If you are using the SAM utility to create volume groups, it creates all possible
alternate links by default.
After the primary link has recovered, LVM will automatically switch the active I/O from the
alternate path to the primary path unless you previously instructed it not to by using the
pvchange LVM command.
After initial volume-group setup, path management is manipulated at the physical-volume level
using HP-UX pv... commands. To display the paths to a device, and the status of each path,
use HP-UX's pvdisplay /dev/dsk/... command. To display the paths to all devices
within a volume-group, use HP-UX's vgdisplay -v command. The following example show
partial output from these commands:
# vgdisplay -v
--- Logical volumes --
Opcode
Page Code
18
-1
Setting Up Multipathing Software on 1 1i v2
Page Offset
SNO length
36
12
33
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