Storage Multi-Pathing choices in HP-UX Serviceguard environments, August 2009

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automatically configured, fully integrated with the rest of HP-UX and can be used with all the HP-UX
I/O commands.
HP-UX 11i v3 does not support HP StorageWorks active/passive disk arrays. If you are using an
active/passive EVA 3000 or 5000 disk arrays, you must upgrade the firmware to an active/active
version.
Additional information on the migration from HP StorageWorks SecurePath to Native Multi-Pathing in
HP-UX 11i v3 can be found in the following white paper: “Migrating from HP StorageWorks SecurePath
for Active-Active Disk Arrays to Native Multipathing in HP-UX 11i v3”.
EMC PowerPath
EMC has released a version of PowerPath for HP-UX 11i v3 to provide customers which dependent
upon PowerPath for operations an easy migration path to HP-UX 11i v3. Version 5.1 of PowerPath
provides path failover and load balancing and is subject to several limitations. For example,
PowerPath Version 5.1 supports only the Legacy style device special files (DSFs) and thus is limited to
11i v2 storage connectivity limits. New style DSFs are not supported with this current version of
PowerPath. For more details, please see: “EMC® PowerPath® for HP-UX Version 5.1 and Service
Pack Releases”. Note that Native Multi-Pathing on HP-UX 11i v3 supports EMC active/active disk
arrays (Symmetrix, DMX) and CX with ALUA compliant firmware).
Metrocluster SRDF was dependent on EMC PowerPath for configuring consistency groups. On HP-UX
11i v3, it will be possible to configure consistency groups through the EMC Enginuity Consistency
Assist (ECA) product and thus removing the dependency of Metrocluster SRDF on EMC PowerPath.
Summary and Recommendation
On HP-UX 11i v2 several multi-pathing solutions exist and the section Selection and coexistence of
different multi-pathing solutions provides some information on how to select between them.
For HP-UX 11i v3 the selection is more straight forward. Since HP StorageWorks SecurePath is not
available and the current version of EMC PowerPath only provides Legacy mode access with
associated limitations, customers that used those solutions on HP-UX 11i v2 will most probably move
to Native Multi-Pathing. The same holds true for customers that implemented PVlinks prior to HP-UX
11i v3 or those that want to deploy VxVM 4.1 on HP-UX 11i v3. For VxVM 5.0 on HP-UX 11i v3 the
customers will have the choice between DMP and Native Multi-Pathing while CVM 5.0 will require
DMP according to the information that was available at the time this white paper was written.