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Chapter 6.
LVM Troubleshooting
This chapter provide instructions for troubleshooting a variety of LVM issues.
6.1. Troubleshooting Diagnostics
If a command is not working as expected, you can gather diagnostics in the following ways:
• Use the -v, -vv, -vvv, or -vvvv argument of any command for increasingly verbose levels of
output.
• If the problem is related to the logical volume activation, set 'activation = 1' in the 'log' section of the
configuration file and run the command with the -vvvv argument. After you have finished examining
this output be sure to reset this parameter to 0, to avoid possible problems with the machine locking
during low memory situations.
• Run the lvmdump command, which provides an information dump for diagnostic purposes. For
information, see the lvmdump(8) man page.
• Execute the lvs -v, pvs -a or dmsetup info -c command for additional system information.
• Examine the last backup of the metadata in the /etc/lvm/backup file and archived versions in
the /etc/lvm/archive file.
• Check the current configuration information by running the lvm dumpconfig command.
• Check the .cache file in the /etc/lvm directory for a record of which devices have physical
volumes on them.
6.2. Displaying Information on Failed Devices
You can use the -P argument of the lvs or vgs command to display information about a failed
volume that would otherwise not appear in the output. This argument permits some operations even
though the metatdata is not completely consistent internally. For example, if one of the devices that
made up the volume group vg failed, the vgs command might show the following output.
[root@link-07 tmp]# vgs -o +devices
Volume group "vg" not found
If you specify the -P argument of the vgs command, the volume group is still unusable but you can
see more information about the failed device.
[root@link-07 tmp]# vgs -P -o +devices
Partial mode. Incomplete volume groups will be activated read-only.
VG
#PV #LV #SN Attr
vg
9
2
vg
9
2
In this example, the failed device caused both a linear and a striped logical volume in the volume
group to fail. The lvs command without the -P argument shows the following output.
VSize VFree Devices
0 rz-pn- 2.11T 2.07T unknown device(0)
0 rz-pn- 2.11T 2.07T unknown device(5120),/dev/sda1(0)
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