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

HP-UX Handbook – Rev 13.00 Page 84 (of 110)
Chapter 13 LVM
October 29, 2013
4. PROBLEM – Hardware issue
Please also bear in mind, that this error, could be due to a hardware problem as well. It
is recommended, that hardware on the system is also checked, to exclude hardware
failures, before further troubleshooting is performed.
Hardware problems on a disk, can be checked with the dd command (for exact options,
check the dd manpage). Please note, that the dd command, alhough completed with
success, is not a guarantee for no hardware issues. It only reads from the disk, and
does not write, so further examinations should be made, in order to make sure, that
hardware problems are not present.
5. PROBLEM – the "couldn't query" message Cur and Act PV number disagree
Typically vgreduce -f is used when the volume group's vgdisplay(1m)
output shows Cur PV and Act PV disagree. Often vgdisplay(1m) will
give a message like: couldn't query physical volume /dev/dsk/cXtXdX when Cur
and Act PV number disagree. The "couldn't query" message usually indicates one
of these scenarios:
1. The disk device(s) specified is not responding due to a hardware error
or incorrect device file. Here are some commands that may help isolate
if there is a disk device problem:
- ioscan -fn
Hardware path should show as claimed and with the correct device file.
- insf -H HW_PATH_FROM_IOSCAN -e
Recreate device file.
- diskinfo /dev/rdsk/cXtXd0
Verify product number and size.
- dd if=/dev/dsk/cXtXdX of=/dev/null bs=10k count=30
Verify the disk can read from without error and the blocks in and out
match. You should get 30+0 records in 30+0 records out.
2. The disk is responding but does not contain correct lvm information to
attach it to the volume group. Every LVM physical volume contains a
volume group reserve area (VGRA) on the front of that disk device. The
VGRA contains information, shared by all disks attached to the same
volume group, to know how disk devices belonging to that volume group are
partitioned. If this area becomes corrupt or overwritten it will result
in the "couldn't query physical volume message" from vgdisplay(1m).