5.4.16.8.2. The warn RAID Fault Policy
In the following example, the
raid_fault_policy field has been set to warn in the lvm.conf file. The RAID logical volume is laid out as follows.
# lvs -a -o name,copy_percent,devices my_vg
LV Copy% Devices
my_lv 100.00 my_lv_rimage_0(0),my_lv_rimage_1(0),my_lv_rimage_2(0)
[my_lv_rimage_0] /dev/sdh1(1)
[my_lv_rimage_1] /dev/sdf1(1)
[my_lv_rimage_2] /dev/sdg1(1)
[my_lv_rmeta_0] /dev/sdh1(0)
[my_lv_rmeta_1] /dev/sdf1(0)
[my_lv_rmeta_2] /dev/sdg1(0)
If the
/dev/sdh device fails, the system log will display error messages. In this case, however, LVM will not automatically attempt to repair the RAID device by replacing one of the images. Instead, if the device has failed you can replace the device with the --repair argument of the lvconvert command, as shown below.
#lvconvert --repair my_vg/my_lv/dev/sdh1: read failed after 0 of 2048 at 250994294784: Input/output error /dev/sdh1: read failed after 0 of 2048 at 250994376704: Input/output error /dev/sdh1: read failed after 0 of 2048 at 0: Input/output error /dev/sdh1: read failed after 0 of 2048 at 4096: Input/output error Couldn't find device with uuid fbI0YO-GX7x-firU-Vy5o-vzwx-vAKZ-feRxfF. Attempt to replace failed RAID images (requires full device resync)? [y/n]:y#lvs -a -o name,copy_percent,devices my_vgCouldn't find device with uuid fbI0YO-GX7x-firU-Vy5o-vzwx-vAKZ-feRxfF. LV Copy% Devices my_lv 64.00 my_lv_rimage_0(0),my_lv_rimage_1(0),my_lv_rimage_2(0) [my_lv_rimage_0] /dev/sde1(1) [my_lv_rimage_1] /dev/sdf1(1) [my_lv_rimage_2] /dev/sdg1(1) [my_lv_rmeta_0] /dev/sde1(0) [my_lv_rmeta_1] /dev/sdf1(0) [my_lv_rmeta_2] /dev/sdg1(0)
Note that even though the failed device has been replaced, the display still indicates that LVM could not find the failed device. This is because, although the failed device has been removed from the RAID logical volume, the failed device has not yet been removed from the volume group. To remove the failed device from the volume group, you can execute
vgreduce --removemissing VG.
If the device failure is a transient failure or you are able to repair the device that failed, as of Red Hat Enterprise Linux release 6.5 you can initiate recovery of the failed device with the
--refresh option of the lvchange command. Previously it was necessary to deactivate and then activate the logical volume.
The following command refreshes a logical volume.
# lvchange --refresh my_vg/my_lv