[linux-lvm] Can't work normally after attaching disk volumes originally in a VG on another machine
Gang He
ghe at suse.com
Mon Mar 26 06:04:23 UTC 2018
Hi Xen,
>>>
> Gang He schreef op 23-03-2018 9:30:
>
>> 6) attach disk2 to VM2(tb0307-nd2), the vg on VM2 looks abnormal.
>> tb0307-nd2:~ # pvs
>> WARNING: Device for PV JJOL4H-kc0j-jyTD-LDwl-71FZ-dHKM-YoFtNV not
>> found or rejected by a filter.
>> PV VG Fmt Attr PSize PFree
>> /dev/vdc vg2 lvm2 a-- 20.00g 20.00g
>> /dev/vdd vg1 lvm2 a-- 20.00g 20.00g
>> [unknown] vg1 lvm2 a-m 20.00g 20.00g
>
> This is normal because /dev/vdd contains metadata for vg1 which includes
> now missing disk /dev/vdc .... as the PV is no longer the same.
>
>
>
>
>> tb0307-nd2:~ # vgs
>> WARNING: Device for PV JJOL4H-kc0j-jyTD-LDwl-71FZ-dHKM-YoFtNV not
>> found or rejected by a filter.
>> VG #PV #LV #SN Attr VSize VFree
>> vg1 2 0 0 wz-pn- 39.99g 39.99g
>> vg2 1 0 0 wz--n- 20.00g 20.00g
>
> This is normal because you haven't removed /dev/vdc from vg1 on
> /dev/vdd, since it was detached while you operated on its vg.
>
>
>> 7) reboot VM2, the result looks worse (vdc disk belongs to two vg).
>> tb0307-nd2:/mnt/shared # pvs
>> PV VG Fmt Attr PSize PFree
>> /dev/vdc vg1 lvm2 a-- 20.00g 0
>> /dev/vdc vg2 lvm2 a-- 20.00g 10.00g
>> /dev/vdd vg1 lvm2 a-- 20.00g 9.99g
>
> When you removed vdd when it was not attached, the VG1 metadata on vdd
> was not altered. The metadata resides on both disks, so you had
> inconsistent metadata between both disks because you operated on the
> shared volume group while one device was missing.
>
> You also did not recreate PV on /dev/vdc so it has the same UUID as when
> it was part of VG1, this is why VG1 when VDD is booted will still try to
> include /dev/vdc because it was never removed from the volume group on
> VDD.
>
> So the state of affairs is:
>
> /dev/vdc contains volume group info for VG2 and includes only /dev/vdc
>
> /dev/vdd contains volume group info for VG1, and includes both /dev/vdc
> and /dev/vdd by UUID for its PV, however, it is a bug that it should
> include /dev/vdc even though the VG UUID is now different (and the name
> as well).
It looks like each PV includes a copy meta data for VG, but if some PV has changed (e.g. removed, or moved to another VG),
the remained PV should have a method to check the integrity when each startup (activated?), to avoid such inconsistent problem automatically.
Thanks
Gang
>
> Regardless, from vdd's perspective /dev/vdc is still part of VG1.
>
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