HP-UX HB v13.00 Ch-13 - LVM

HP-UX Handbook – Rev 13.00 Page 104 (of 110)
Chapter 13 LVM
October 29, 2013
Booting:
When LVM Data Structures Are Lost
When critical LVM data structures have been lost, you will need to use the recovery
portion of the Support Media included in the HP-UX product kit to restore the corrupted
disk image from your backup tape. For more information, see the Support Media User's
Manual.
After you have made the LVM disk minimally bootable, the system can be booted in
maintenance mode using the -lm option of the hpux command at the ISL> prompt. This
causes the system to boot to single-user state without primary swap, dump, or LVM to
access the root file system. See "Booting in Maintenance Mode" in Chapter 2 for more
information. (The information is identical for Series 700 or 800 systems.)
CAUTION: The system must not be brought to multi-user mode (that is, run-level 2 or
greater) when in LVM maintenance mode. Corruption of the root file system might
result.
To exit LVM maintenance mode, use reboot -n.
When a Volume Group Will Not Activate
Normally, volume groups are automatically activated during system startup. Unless you
intentionally deactivate a volume group using vgchange, you will probably not need to
reactivate a volume group.
However, LVM does require that a "quorum" of disks in a volume group be available.
During normal system operation, LVM needs a quorum of more than half of the disks in
a volume group for activation. If, during run time, a disk fails and causes quorum to be
lost, LVM alerts you with a message to the console, but keeps the volume group active.
When booting the system, LVM also will require a quorum of one more than half of the
disks in the root volume group. This means, for example, that LVM cannot activate a
two-disk root volume group with one of the disks offline. As a result, if this happens, you
will have a problem booting.
Another possible problem pertaining to activation of a volume group is a missing or
corrupted /etc/lvmtab file. You can use the vgscan(1M) command to re-create the
/etc/lvmtab file.