HP-UX Logical Volume Manager and MirrorDisk/UX Release Notes (September 2007)

NOTE: HP recommends using the multi-pathing features provided by the mass storage

stack instead of LVM's alternate links, as described in “Moving from HP-UX 11i v2 to HP-UX

11i v3” (page 9). The proactive polling feature is provided for backward compatibility with

previous releases, or if native multi-pathing is disabled. HP recommends configuring LVM

volume groups using persistent device special files.

The following MirrorDisk/UX feature is new with the September 2007 release of HP-UX 11i v3:

• Parallel Resynchronization of Stale Extents: This release introduces new command line

options to the lvextend, lvmerge, and lvsync commands that enable the user to control

the synchronization of stale extents.

Normally, when mirrored logical volumes are created, extended, or merged using the

lvextend and lvmerge commands, any stale extents are automatically synchronized

before the commands complete. Even if multiple commands are run in parallel, a locking

mechanism forces them to synchronize serially. This may not be desirable if many such

operations are to be performed, as in the mirroring of an entire volume group.

A new command line option, -s , has been added to the lvmerge and lvextend commands.

This option suppresses the automatic synchronization of stale extents. Note that

synchronization is still necessary but can be done using the lvsync command.

A new command line option, -T, has been added to the lvsync command. This option

resynchronizes the specified logical volumes in parallel rather than serially. In many cases

this will reduce the time needed to synchronize the stale extents.

As an example, the Mirroring the Boot Disk section of the HP-UX System Administrator's Guide:

Logical Volume Management contains the following series of commands:

# lvextend –m 1 /dev/vg00/lvol1 /dev/disk/disk4

The newly allocated mirrors are now being synchronized.