Installation guide

Chapter 6. LVM Troubleshooting

[root@link-07 tmp]# lvs -a -o +devices

Volume group "vg" not found

Using the -P argument shows the logical volumes that have failed.

[root@link-07 tmp]# lvs -P -a -o +devices

Partial mode. Incomplete volume groups will be activated read-only.

LV VG Attr LSize Origin Snap% Move Log Copy% Devices

linear vg -wi-a- 20.00G unknown device(0)

stripe vg -wi-a- 20.00G unknown device(5120),/dev/sda1(0)

The following examples show the output of the pvs and lvs commands with the -P argument

specified when a leg of a mirrored logical volume has failed.

root@link-08 ~]# vgs -a -o +devices -P

Partial mode. Incomplete volume groups will be activated read-only.

VG #PV #LV #SN Attr VSize VFree Devices

corey 4 4 0 rz-pnc 1.58T 1.34T my_mirror_mimage_0(0),my_mirror_mimage_1(0)

corey 4 4 0 rz-pnc 1.58T 1.34T /dev/sdd1(0)

corey 4 4 0 rz-pnc 1.58T 1.34T unknown device(0)

corey 4 4 0 rz-pnc 1.58T 1.34T /dev/sdb1(0)

[root@link-08 ~]# lvs -a -o +devices -P

Partial mode. Incomplete volume groups will be activated read-only.

LV VG Attr LSize Origin Snap% Move Log Copy% Devices

my_mirror corey mwi-a- 120.00G my_mirror_mlog 1.95

my_mirror_mimage_0(0),my_mirror_mimage_1(0)

[my_mirror_mimage_0] corey iwi-ao 120.00G unknown

device(0)

[my_mirror_mimage_1] corey iwi-ao 120.00G /dev/

sdb1(0)

[my_mirror_mlog] corey lwi-ao 4.00M /dev/

sdd1(0)

6.3. Recovering from LVM Mirror Failure

This section provides an example of recovering from a situation where one leg of an LVM

mirrored volume fails because the underlying device for a physical volume goes down and the

mirror_log_fault_policy parameter is set to remove, requiring that you manually rebuild the

mirror. For information on setting the mirror_log_fault_policy parameter, refer to Section 6.3,

“Recovering from LVM Mirror Failure”.

When a mirror leg fails, LVM converts the mirrored volume into a linear volume, which continues to

operate as before but without the mirrored redundancy. At that point, you can add a new disk device to

the system to use as a replacement physical device and rebuild the mirror.

The following command creates the physical volumes which will be used for the mirror.

[root@link-08 ~]# pvcreate /dev/sd[abcdefgh][12]

Physical volume "/dev/sda1" successfully created

Physical volume "/dev/sda2" successfully created

Physical volume "/dev/sdb1" successfully created

Physical volume "/dev/sdb2" successfully created