6.2. Displaying Information on Failed Devices

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   VSize VFree Devices
  vg     9   2   0 rz-pn- 2.11T 2.07T unknown device(0)
  vg     9   2   0 rz-pn- 2.11T 2.07T unknown device(5120),/dev/sda1(0)

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. 

[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)

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