HP-UX 11i v3 Native Multi-Pathing for Mass Storage (September 2009)

For more information, see the LVM Migration from Legacy to Agile Naming Model HP-UX 11i v3

white paper.

File systems

In HP-UX 11i v3, HFS supports both legacy and persistent LUN DSFs. Therefore, HFS takes advantage

of multi-pathing by default. For support of VxFS on HP-UX 11iv3, see the release notes from

Symantec.

Commands

Existing commands such as

ioscan and sar have evolved to use multi-pathing. New options have

been introduced. For information on the changes, see

ioscan(1M), sar(1M), and the HP-UX 11i v3

Release Notes.

Compatibility with the legacy naming model

By default, native multi-pathing applies to legacy DSFs even though a legacy DSF corresponds to a

lunpath to a LUN. When an application accesses a legacy DSF, the mass storage subsystem internally

applies the configured LUN level multi-pathing (I/O load balancing, automated path failure detection

and recovery) to send I/O requests to the end LUN. This enables applications migrating to HP-UX 11i

v3 to take advantage of multi-pathing: no special configuration is needed.

At the same time, the mass storage subsystem is flexible to accommodate the strict backward

compatibility needs of some applications by allowing disabling of native multi-pathing on legacy DSFs

with a tunable. See Setting Native Multi-Pathing support on legacy DSFs

Pre-HP-UX 11i v3 multi-pathing add-on products are no longer required

HP add-on AutoPath® and SecurePath® products are no longer supported with HP-UX 11i v3. For

more information, see the Migrating from HP Storage Works Secure Path for Active-Active Disk Arrays

to Native Multipathing in HP-UX 11i v3 white paper.

To determine if other add-on multi-pathing products are supported on HP-UX 11i v3, see their

associated release notes.

Managing HP-UX 11i v3 native multi-pathing

To illustrate the management of multi-pathing on HP-UX 11iv3, Figure 1 shows a SAN comprising the

following:

• A server running HP-UX 11i v3. It is connected to the SAN via two host bus adapters (HBAs)

• A disk array with five LUN devices connected to the SAN via two target ports