HP-UX Logical Volume Manager and MirrorDisk/UX Release Notes (762804-001, March 2014)

Alternatively, you can disable multipathing for all legacy device files with this command:
# scsimgr save_attr -a leg_mpath_enable=false
Note that this has no effect on multipathing through persistent device special files. For more
information, see scsimgr(1M).
1.6.4 Moving volume groups from HP-UX 11i v3 to previous HP-UX releases
If a volume group used on HP-UX 11i v3 is accessed from a system running a previous release of
HP-UX 11i, you might encounter these compatibility issues:
• Version 2.x volume groups: As noted in “Version 2.x volume groups” (page 12), Version 2.x
volume groups are not recognized on previous releases of HP-UX.
• Logical volumes larger than 2 TB: Releases prior to HP-UX 11i v3 can only access data within
the first 2 TB of a logical volume. If a logical volume larger than 2 TB is created on HP-UX 11i
v3, its use is not recommended on any previous HP-UX release. The volume group can be
activated and the logical volume can be used, but any data in that logical volume beyond 2
TB will be inaccessible.
NOTE: Patches PHKL_36745, PHCO_36744, and PHCO_37939 resolve this compatibility
issue for HP-UX 11i v2. Installing these patches enables the creation and use of logical volumes
up to 16 TB.
• Striped Mirrors: Releases prior to HP-UX 11i v3 only support extent-based striping via the -D
option to lvcreate. If a logical volume using simultaneous mirroring and non-extent-based
striping is created on HP-UX 11i v3, attempts to import or activate its associated volume group
will fail on a previous HP-UX release. To import the volume group, you must remove the
incompatible logical volumes or reduce them to a single mirror.
NOTE: Patches PHKL_36745, PHCO_36744, and PHCO_37939 resolve this compatibility
issue for HP-UX 11i v2. Installing these patches enables the creation and use of striped mirrors.
• Mirror Write Cache (MWC): When a volume group containing a logical volume using the
Mirror Write Cache is activated on HP-UX 11i v3, its Mirror Write Cache format is converted
to a new format. Importing or activating the volume group on a previous HP-UX release does
not recognize the new format and triggers a full resynchronization of the mirrors.
NOTE: Patch PHKL_36244 adds support for the new MWC format to HP-UX 11i v2. Installing
this patch avoids the unnecessary resynchronization.
In the future, HP might add support of larger logical volumes and striped mirrors to previous releases
of HP-UX 11i. However,
As of this writing, larger logical volumes and striped mirrors are only available on HP-UX 11i v3
and HP-UX 11i v2 (with patches). For up-to-the-moment information, contact your Hewlett-Packard
support representative or consult the Hewlett-Packard IT Resource Center site: www.hp.com/go/
hpsc for LVM patches.
1.6 Compatibility issues 13