Hi,
I am encountering strange behaviour when trying to recover a Raid 10 LV,
created with the following command:
lvcreate --type raid10 -L3G -i 2 -I 256 -n lv_r10 vg_data /dev/vdb1:1-500
/dev/vdc1:1-500 /dev/vdd1:1-500 /dev/vde1:1-500
As it can be seen, I have 4 PVs and give the first 500 PE of each of them for
the raid 10 logical volume. I am able to see the following PE layout:
lvs -o seg_pe_ranges,lv_name,stripes -a
PE Ranges
LV #Str
lv_r10_rimage_0:0-767 lv_r10_rimage_1:0-767 lv_r10_rimage_2:0-767
lv_r10_rimage_3:0-767 lv_r10 4
/dev/vdb1:2-385
[lv_r10_rimage_0] 1
/dev/vdc1:2-385
[lv_r10_rimage_1] 1
/dev/vdd1:2-385
[lv_r10_rimage_2] 1
/dev/vde1:2-385
[lv_r10_rimage_3] 1
/dev/vdb1:1-1
[lv_r10_rmeta_0] 1
/dev/vdc1:1-1
[lv_r10_rmeta_1] 1
/dev/vdd1:1-1
[lv_r10_rmeta_2] 1
/dev/vde1:1-1
[lv_r10_rmeta_3] 1
So far everything is OK and the number of PE is automatically reduced to 385
per PV to have the size equal to 3 Gigabytes.
The problem comes when I shut down the system, replace one disk (vdc), boot
again and try to recover the array. Here are the commands I execute:
pvs
Couldn't find device with uuid 2hU2pD-xNDa-yi1J-OkkP-NjGq-hIxo-Q5AgQC.
PV VG Fmt Attr PSize PFree
/dev/vdb1 vg_data lvm2 a-- 8.00g 6.49g
/dev/vdd1 vg_data lvm2 a-- 8.00g 6.49g
/dev/vde1 vg_data lvm2 a-- 8.00g 6.49g
unknown device vg_data lvm2 a-m 8.00g 6.49g
pvcreate /dev/vdc1
Physical volume "/dev/vdc1" successfully created
vgextend vg_data /dev/vdc1
Couldn't find device with uuid 2hU2pD-xNDa-yi1J-OkkP-NjGq-hIxo-Q5AgQC
Volume group "vg_data" successfully extended
lvs -o seg_pe_ranges,lv_name,stripes -a
Couldn't find device with uuid 2hU2pD-xNDa-yi1J-OkkP-NjGq-hIxo-Q5AgQC.
PE Ranges
LV #Str
lv_r10_rimage_0:0-767 lv_r10_rimage_1:0-767 lv_r10_rimage_2:0-767
lv_r10_rimage_3:0-767 lv_r10 4
/dev/vdb1:2-385
[lv_r10_rimage_0] 1
unknown device:2-385
[lv_r10_rimage_1] 1
/dev/vdd1:2-385
[lv_r10_rimage_2] 1
/dev/vde1:2-385
[lv_r10_rimage_3] 1
/dev/vdb1:1-1
[lv_r10_rmeta_0] 1
unknown device:1-1
[lv_r10_rmeta_1] 1
/dev/vdd1:1-1
[lv_r10_rmeta_2] 1
/dev/vde1:1-1
[lv_r10_rmeta_3] 1
lvchange -ay --partial /dev/vg_data/lv_r10
PARTIAL MODE. Incomplete logical volumes will be processed.
Couldn't find device with uuid 2hU2pD-xNDa-yi1J-OkkP-NjGq-hIxo-Q5AgQC
lvconvert --repair vg_data/lv_r10 /dev/vdc1:1-385
Attempt to replace failed RAID images (requires full device resync)? [y/n]: y
Insufficient free space: 770 extents needed, but only 345 available
Failed to allocate replacement images for vg_data/lv_r10
lvconvert --repair vg_data/lv_r10
Attempt to replace failed RAID images (requires full device resync)? [y/n]: y
Faulty devices in vg_data/lv_r10 successfully replaced.
lvs -o seg_pe_ranges,lv_name,stripes -a
Couldn't find device with uuid
2hU2pD-xNDa-yi1J-OkkP-NjGq-hIxo-Q5AgQC.
PE Ranges
LV #Str
lv_r10_rimage_0:0-767 lv_r10_rimage_1:0-767 lv_r10_rimage_2:0-767
lv_r10_rimage_3:0-767 lv_r10 4
/dev/vdb1:2-385
[lv_r10_rimage_0] 1
/dev/vdc1:1-768
[lv_r10_rimage_1] 1
/dev/vdd1:2-385
[lv_r10_rimage_2] 1
/dev/vde1:2-385
[lv_r10_rimage_3] 1
/dev/vdb1:1-1
[lv_r10_rmeta_0] 1
/dev/vdc1:0-0
[lv_r10_rmeta_1] 1
/dev/vdd1:1-1
[lv_r10_rmeta_2] 1
/dev/vde1:1-1
[lv_r10_rmeta_3] 1
The array was recovered, but it is definitely not what I expected, because on
/dev/vdc1 now 768 PEs are used instead of 385, like on the other PVs. In this
case I had some extra free space on /dev/vdc1, but what if I did not? Please,
suggest what should be done.
Linux ubuntu1 3.13.0-32-generic, x86_64
LVM version: 2.02.98(2) (2012-10-15)
Library version: 1.02.77 (2012-10-15)
Driver version: 4.27.0
Pavlik Petrov
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