Managing Systems and Workgroups: A Guide for HP-UX System Administrators

Administering a System: Managing Disks and Files
Managing Disks
Chapter 6 597
As a result, the volume group will activate without a quorum being
present. You might get messages about not being able to access
certain logical volumes. This is because part or all of a logical volume
might be located on one of the disks that is not present.
Whenever you override a quorum requirement, you run the risk of
using data that are not current. Be sure to check the data on the
logical volumes in the activated volume group as well as the size and
locations of the logical volumes to ensure that they are up-to-date.
You should attempt to return the disabled disks to the volume group
as soon as possible. When you return a disk to service that was not
online when you originally activated the volume group, you should
once again use vgchange.
vgchange -a y /dev/vg01
Quorum Problems
with Your Root
Volume Group
Your root volume group might also have a quorum problem. If there are
not enough disks present in the root volume group to constitute a
quorum, a message indicating that not enough physical volumes are
present will be displayed during the boot sequence. This might occur if
you have physically removed a disk from your system because you no
longer intended to use it with the system, but did not remove the
physical volume from the volume group using vgreduce. Although you
should never remove an LVM disk from a system without first removing
it from its volume group, you can probably recover from this situation by
booting your system with the quorum override option, hpux -lq.
Problems After Reducing the Size of a Logical Volume
When a file system is first created within a logical volume, it is made as
large as the logical volume will permit.
If you extend the logical volume without extending its file system, you
can subsequently safely reduce the logical volume’s size as long as it
remains as big as its file system. (Use bdf (1M) to determine the size of
your file system.) Once you use the extendfs command to expand the file
system, you can no longer safely reduce the size of the associated logical
volume.
If you reduce the size of a logical volume containing a file system to a size
smaller than that of a file system within it using the lvreduce
command, you will corrupt the file system. If you subsequently attempt
to mount the corrupt file system, you may crash your system. If this
occurs: