[linux-lvm] VG won't activate -- dm problem

[Scott Hazelhurst]

Dear all

I did an upgrade of my Ubuntu 16.04.2 system and when I rebooted my key volume group won’t activate properly. If I do a pvs, vgs, or lvs all the volumes appear good but dmsetup doesn’t show any information

For example I do this and I see the volume (VM70POOL is the VG I am interested in)

vgs

VG #PV #LV #SN Attr VSize VFree
VM70POOL 1 11 0 wz--n- 1.82t 1.08t
ubuntu-vg 2 2 0 wz--n- 3.64t 48.19g

and
***@vmhost:/var/log# lvdisplay /dev/VM70POOL/health-root-1610
--- Logical volume ---
LV Path /dev/VM70POOL/health-root-1610
LV Name health-root-1610
VG Name VM70POOL
LV UUID jVkRfy-tQ6M-D9RM-xcvO-NxGX-24RY-jQv1r1
LV Write Access read/write
LV Creation host, time vmhost, 2016-11-16 10:10:58 +0200
LV Status NOT available
LV Size 64.00 GiB
Current LE 16384
Segments 1
Allocation inherit
Read ahead sectors auto


But I can’t activate the volume — I get

***@vmhost:/var/log# vgchange -ay VM70POOL
device-mapper: reload ioctl on (252:6) failed: Device or resource busy
device-mapper: reload ioctl on (252:6) failed: Device or resource busy
device-mapper: reload ioctl on (252:6) failed: Device or resource busy
device-mapper: reload ioctl on (252:6) failed: Device or resource busy
device-mapper: reload ioctl on (252:6) failed: Device or resource busy
device-mapper: reload ioctl on (252:6) failed: Device or resource busy
device-mapper: reload ioctl on (252:6) failed: Device or resource busy
device-mapper: reload ioctl on (252:6) failed: Device or resource busy
device-mapper: reload ioctl on (252:6) failed: Device or resource busy
device-mapper: reload ioctl on (252:6) failed: Device or resource busy
device-mapper: reload ioctl on (252:6) failed: Device or resource busy
0 logical volume(s) in volume group "VM70POOL" now active

and in kern.log we have "kernel: [ 3819.113149] device-mapper: table: 252:6: linear: Device lookup failed"

Indeed there is no /dev/dm-6 or above

and dmsetup ls shows no sign of the volume
***@vmhost:/var/log# dmsetup ls --tree -o device
ubuntu--vg-swap_1 (252:5)
└─ (8:5)
ubuntu--vg-root (252:4)
├─ubuntu--vg-root_rimage_1 (252:3)
│ └─ (8:21)
├─ubuntu--vg-root_rmeta_1 (252:2)
│ └─ (8:21)
├─ubuntu--vg-root_rimage_0 (252:1)
│ └─ (8:5)
└─ubuntu--vg-root_rmeta_0 (252:0)
└─ (8:5)



For the record
***@vmhost:/var/log#***@vmhost:/var/log# pvdisplay
--- Physical volume ---
PV Name /dev/sdc
VG Name VM70POOL
PV Size 1.82 TiB / not usable 1.09 MiB
Allocatable yes
PE Size 4.00 MiB
Total PE 476932
Free PE 284420
Allocated PE 192512
PV UUID X2Pzgr-nqNp-ri8n-HoT6-Zs7y-e7FC-sNURM6




smartmon shows no problem with the disk though I realize that doesn’t necessarily mean anything


FWIW, in one posting I found that someone with a similar problem had there was a suggestion to do vgscan —mknodes
This had no effect.

I have rebooted the machine too

Any suggestions gratefully received?

Many thanks

Scott






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[Scott Hazelhurst]

A couple of days ago I raised the problem of not being able to activate a volume group, and getting an error message device-mapper: reload ioctl on (252:6) failed: Device or resource busy.

In case, this is of help to anyone else, I found the problem. The PV for the volume group was /dev/sdc. About 18 months ago, it was part of a software raid volume (not using LVM). I decided not to run RAID and disabled it. All was fine for a long time through various OS updates and machine reboots. However, after I upgraded Ubuntu from 14.04 to 16.04, something got reactivated in some way. I presume I did something wrong originally. [As an aside I have checked and another of my machines that went through the same update had the same problem]

So here the error message was relatively spot on. I was distracted by the 252:6 part of the message and the absence of /dev/dm-6. The VG could not be activated because the raid was managing it. I used mdadm to stop and delete the RAID and restarted and all is well.

Scott



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