Chapter 8 Setting The Multipaths; Multipath Configuration Using Pv-Links - Fujitsu ETERNUS DX Configuration Manual

Chapter 8
Setting the Multipaths
Two types of multipath configurations are available for the connection between the ETERNUS DX and an HP-
UX server: "PV-Links" and "Native Multipaths".
This chapter explains how to set up the "PV-Links" or "Native Multipaths".
8.1

Multipath Configuration using PV-Links

PV-Links" is a Logical Volume Manager (LVM) function, available for all HP-UX versions.
LVM for HP-UX supplies PV-Links as a standard function for configuring paths in a redundant configuration
(path failover function).
PV-Links is set by including multiple paths connected to one physical volume in one volume group.
Only one of the paths will be set as the Active path, with the other paths being made Standby paths.
However, load on the system may be better balanced by spreading the server accesses over multiple Active
paths.
When using PV-Links, note the following:
Confirm that the PV-Links paths have identical target IDs.
•
When set correctly, the device files for all paths that connect to a given ETERNUS DX LUN should all be the
same after the "t" part of the name (e.g. "/dev/dsk/c4t0d0" g"0d0").
For HP-UX11iv3, set the "leg_mpath_enable" parameter to "false" and use LegacyDSF to specify the
•
"pv_path" parameter to create VolumeGroup.
Reference
-
Device special file type
Legacy DSF
Persistent DSF
Example:
-
Setting "leg_mpath_enable" to "false"
# scsimgr save_attr -D /dev/rdisk/disk25 -a leg_mpath_enable=false
Using LegacyDSF to specify the "pv_path" parameter to create VolumeGroup
# vgcreate vg01 /dev/dsk/c4t0d0 /dev/dsk/c6t0d0
FUJITSU Storage ETERNUS DX Configuration Guide -Server Connection- (iSCSI) for HP-UX
Example device special file
/dev/dsk/c4t0d0
/dev/rdsk/c4t0d0
/dev/disk/disk25
/dev/rdisk/disk25
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