HP-UX Logical Volume Manager and MirrorDisk/UX Release Notes (March 2008)

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 may encounter these compatibility issues:

• Version 2.0 volume groups: As noted in “Version 2.0 Volume Groups” (page 12), Version

2.0 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 and PHCO_36746 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 and PHCO_36746 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: PHKL_36244 adds support for the new MWC format to HP-UX 11i v2. Installing

that patch avoids the unnecessary resynchronization.