[linux-lvm] Problem with vgreduce on LVM1

Thu Sep 7 17:11:01 UTC 2006

I was actually able to remove one of the PVs from our VG after manually 
altering the lv_cur count on the PV. What follows are the results of the 
operation.

[root at linux /]# vgreduce data /dev/emcpowera
vgreduce -- ERROR "Operation not permitted" reducing volume group "data" 
by physical volume "/dev/emcpowera" in kernel
[root at linux /]# pvdata /dev/emcpowera | grep Cur
Cur LV 0
[root at linux /]# perl -e 'open F, "+<", "/dev/emcpowerb";binmode F;seek 
F,0x1c0,0;$a=getc(F);printf("Before: 0x%x\n",ord($a));seek 
F,0x1c0,0;print F "\0";seek F,0x1c0,0;$a=getc(F);printf("After: 
0x%x\n",ord($a));close F'
Before: 0x4
After: 0x0
--- reboot ---
[root at linux /]# vgreduce data /dev/emcpowera
vgreduce -- doing automatic backup of volume group "data"
vgreduce -- volume group "data" successfully reduced by physical volume:
vgreduce -- /dev/emcpowera

However, for some odd reason which I haven't determined yet, the other 
PV is still erroring out on a reduce after I alter its lv_cur count. It 
is returning the following error.

[root at linux root]# vgreduce data /dev/emcpowerb
vgreduce -- ERROR "parameter error" reducing volume group "data" by 
physical volume "/dev/emcpowerb" in kernel

Is there anyone out there? Who owns LVM1 currently? The other PVs in 
this system still suffer from an incorrect lv_cur count.

Thanks,
Peter

Peter Smith wrote:

> To make matters worse, on a test system I set up a similar group of 
> LVs. Then I removed the first LV and deactivated the VG. At that point 
> I manually editted the disk structure to change the lv_cur on the PV 
> from 0 to something greater than 0 (5 in this case.) Since that's what 
> I think might be in error on my production VG. I expected it to 
> produce the same error when trying to reduce the VG by this PV. It 
> didn't. I'm stumped now.
>
> Peter
>
> Peter Smith wrote:
>
>> You are correct, this action is being barred by the fact that this PV 
>> thinks it still has LVs on it, which is not true. The "Cur LV 4" is 
>> not true. Now I have to figure out why the VG seems to think that 
>> this PV still has 4 LVs on it..
>>
>> Peter
>>
>> Peter Smith wrote:
>>
>>> I'm currently looking at the source code. Meanwhile, if anyone is 
>>> inclined to look, I've captured the output of a "vgreduce data 
>>> /dev/emcpowera -d" [1]...
>>>
>>> Thanks,
>>> Peter
>>>
>>> [1] http://swlxrpx1.swmed.edu/for-linux-lvm-list-001
>>>
>>>
>>> Peter Smith wrote:
>>>
>>>> Well, that is interesting. When I do a "pvdata", it does show an 
>>>> extent in use, one for each of the other LVs, but that is true for 
>>>> all the PVs for some reason. Any ideas on how to stop that? I've 
>>>> already tried a "pvmove" and it says the disk is empty.
>>>>
>>>> [root at linux archive]# pvdata /dev/emcpowera
>>>> --- Physical volume ---
>>>> PV Name /dev/emcpowera
>>>> VG Name data
>>>> PV Size 785.10 GB [1646481408 secs] / NOT usable 1 GB [LVM: 127 KB]
>>>> PV# 1
>>>> PV Status available
>>>> Allocatable NO
>>>> Cur LV 4
>>>> PE Size (KByte) 1048576
>>>> Total PE 784
>>>> Free PE 784
>>>> Allocated PE 0
>>>> PV UUID JpYFFb-NUqC-trBf-oFm7-tbdF-65If-GZ56fw
>>>>
>>>> --- Volume group ---
>>>> VG Name
>>>> VG Access read/write
>>>> VG Status NOT available/resizable
>>>> VG # 0
>>>> MAX LV 256
>>>> Cur LV 5
>>>> Open LV 0
>>>> MAX LV Size 2 TB
>>>> Max PV 256
>>>> Cur PV 8
>>>> Act PV 1
>>>> VG Size 12.21 TB
>>>> PE Size 1 GB
>>>> Total PE 12507
>>>> Alloc PE / Size 9078 / 886 GB
>>>> Free PE / Size 3429 / 3.35 TB
>>>> VG UUID 5Xw9D6-qqfu-0FTg-P9pD-40NH-wRgR-wN03ip
>>>>
>>>> --- List of logical volumes ---
>>>>
>>>> pvdata -- logical volume struct at offset 0 is empty
>>>> pvdata -- logical volume "/dev/data/data2" at offset 1
>>>> pvdata -- logical volume "/dev/data/data3" at offset 2
>>>> pvdata -- logical volume "/dev/data/data4" at offset 3
>>>> pvdata -- logical volume "/dev/data/data5" at offset 4
>>>> pvdata -- logical volume "/dev/data/data6" at offset 5
>>>> pvdata -- logical volume struct at offset 6 is empty
>>>> pvdata -- logical volume struct at offset 7 is empty
>>>> pvdata -- logical volume struct at offset 8 is empty
>>>> pvdata -- logical volume struct at offset 9 is empty
>>>> <SNIP>
>>>> pvdata -- logical volume struct at offset 254 is empty
>>>> pvdata -- logical volume struct at offset 255 is empty
>>>> --- List of physical volume UUIDs ---
>>>>
>>>> 001: JpYFFb-NUqC-trBf-oFm7-tbdF-65If-GZ56fw
>>>> 002: ABNwWZ-h4la-KTcv-VukV-T8vV-PIEP-mm38cy
>>>> 003: oyjw8S-B1gu-snoN-k54q-bCEy-daqn-BYdDmK
>>>> 004: URW9Kt-ZbOn-Ov3h-ZiT5-i7aC-8Lpq-c0fp4l
>>>> 005: y16lho-UgMJ-1lfJ-GNTi-VXWH-Pot1-iIsOc0
>>>> 006: WEC9g3-fTKD-k8pV-Nnxq-Kwn3-EkNd-qV3lUE
>>>> 007: TCxHIb-uvjC-6xap-bLaM-lVJU-N82x-XWd10g
>>>> 008: fZkmf8-jaYW-1gZ6-WBqp-eNu2-s1xr-IBLQTe
>>>>
>>>> Thanks,
>>>> Peter
>>>>
>>>>
>>>> mghofran at caregroup.harvard.edu wrote:
>>>>
>>>>> You show lv=4 so don't you need to check if any of those lvols were
>>>>> using that particular disk, remove the lvol and then proceed?
>>>>>
>>>>> -----Original Message-----
>>>>> From: linux-lvm-bounces at redhat.com 
>>>>> [mailto:linux-lvm-bounces at redhat.com]
>>>>> On Behalf Of Peter Smith
>>>>> Sent: Tuesday, August 29, 2006 12:21 PM
>>>>> To: linux-lvm at redhat.com
>>>>> Subject: [linux-lvm] Problem with vgreduce on LVM1
>>>>>
>>>>> I can't seem to remove two physical volumes. I've removed the LVs 
>>>>> on them. I've deactivated the PVs. But I can not remove the PVs 
>>>>> from the
>>>>> VG.
>>>>>
>>>>> Here's an example of what I'm seeing:
>>>>>
>>>>> [root at linux archive]# pvmove -v /dev/emcpowera
>>>>> pvmove -- checking name of source physical volume "/dev/emcpowera"
>>>>> pvmove -- locking logical volume manager
>>>>> pvmove -- reading data of source physical volume from 
>>>>> "/dev/emcpowera"
>>>>> pvmove -- checking volume group existence
>>>>> pvmove -- reading data of volume group "data" from lvmtab
>>>>> pvmove -- checking volume group consistency of "data"
>>>>> pvmove -- searching for source physical volume "/dev/emcpowera" in 
>>>>> volume group "data"
>>>>> pvmove -- no logical volumes on empty source physical volume 
>>>>> "/dev/emcpowera"
>>>>>
>>>>> [root at linux archive]# vgreduce data /dev/emcpowera
>>>>> vgreduce -- ERROR: can't reduce volume group "data" by used 
>>>>> physical volume "/dev/emcpowera"
>>>>>
>>>>> [root at linux archive]# pvdisplay /dev/emcpowera
>>>>> --- Physical volume ---
>>>>> PV Name /dev/emcpowera
>>>>> VG Name data
>>>>> PV Size 785.10 GB [1646481408 secs] / NOT usable 1 GB [LVM: 127 KB]
>>>>> PV# 1
>>>>> PV Status available
>>>>> Allocatable NO
>>>>> Cur LV 4
>>>>> PE Size (KByte) 1048576
>>>>> Total PE 784
>>>>> Free PE 784
>>>>> Allocated PE 0
>>>>> PV UUID JpYFFb-NUqC-trBf-oFm7-tbdF-65If-GZ56fw
>>>>>
>>>>> Does anyone have any idea why I can't complete a reduce?
>>>>>
>>>>> Thanks,
>>>>> Peter
>>>>>
>>>>> Note:
>>>>> Logical Volume Manager 1.0.8-13
>>>>> Heinz Mauelshagen, Red Hat 03/05/2005 (IOP 10)
>>>>
>