HP-UX Logical Volume Manager and MirrorDisk/UX Release Notes HP-UX 11i v3 (April 2011 web release)

environments, plus selected non-HP servers that have a support obligation with HP. It is
integrated with HP Systems Insight Manager. A dedicated server is recommended to host both
HP Systems Insight Manager and HP Insight Remote Support Advanced.
Go to http://www.hp.com/go/insightremotesupport for details on both versions.
To download the software, go to Software Depot: http://hp.com/go/softwaredepot
Select Insight Remote Support from the menu on the right.
Compatibility issues
Version 2.x volume groups
• Version 2.2 volume groups are not recognized on previous releases of HP-UX, including
versions of HP-UX 11i v3 prior to the March 2010 Update release. Version 2.1 volume groups
are not recognized on previous releases of HP-UX, including versions of HP-UX 11i v3 prior
to the September 2008 release. Version 1.0 volume groups are supported on all supported
versions of HP-UX, including 11i v1, 11i v2, and 11i v3.
• The following HP-UX product does not currently support Version 2.x volume groups:
◦ HP Process Resource Manager (HP PRM)
This product plans to add support of Version 2.x volume groups. For the most recent information
on this products, see the IT Resource Center (ITRC) at http://itrc.hp.com, or consult the release
notes for the specific product.
Encrypted Volume and File System (EVFS) v1.1 and greater supports Version 2.x volume groups.
Moving from HP-UX 11i v2 to HP-UX 11i v3
If you are migrating a system from HP-UX 11i v2 to HP-UX 11i v3, see the LVM migration white
paper described in “Related documentation”. It contains information on migrating an LVM
configuration from the legacy naming model to the agile naming model.
Existing LVM configurations created on HP-UX 11i v2 continue to work on HP-UX 11i v3 under the
legacy naming model. However, there is a change in behavior for Alternate Links (PVLinks):
In HP-UX 11i v3, management of multipathed devices is available outside of LVM using the next
generation mass storage stack. By default, the next generation mass storage stack distributes I/O
requests across all available paths to a multipathed disk, even when using legacy device special
files. Using LVM with persistent or legacy device special files might cause I/O requests to be sent
across alternate links, even if the links are not configured as PVLinks; this does not introduce any
errors, but it does differ from PVLink behavior in previous releases.
When using LVM configuration commands on legacy device special files, LVM does not select an
alternate path if the path corresponding to the specified device special file is unavailable, unless
the unavailable path and the alternate path are configured as part of an active volume group.
When using LVM configuration commands on persistent device special files, LVM succeeds if at
least one of the paths to the device is available.
HP recommends converting volume groups with multipathed disks to persistent device special files
and using native multipathing, as described in the migration white paper in “Related
documentation”.
However, if you want backward-compatible PVLink behavior, you must use legacy device special
files for physical volumes, and disable the mass storage stack multipathing for those physical
volumes. To disable multipathing on legacy device special files, use the scsimgr command to
configure a global device tunable called leg_mpath_enable.
For each multipathed disk, enter the following command:
# scsimgr save_attr -D /dev/rdisk/diskn -a leg_mpath_enable=false
Alternatively, you can disable multipathing for all legacy device files with this command:
8 Logical Volume Manager and MirrorDisk/UX Release Notes