[CentOS] Found duplicate PV

Wed Dec 4 15:28:16 UTC 2013
Pavel Lisy <pavel.lisy at gmail.com>

Markus Falb píše v St 04. 12. 2013 v 15:44 +0100:
> On 04.Dez.2013, at 15:08, Nux! wrote:
> 
> > On 04.12.2013 13:43, Markus Falb wrote:
> >> 
> >> What does this "Found duplicate PV b79x0kLXR9mAC0z0IZUxyJG1VC24Crl7:
> >> using /dev/sda2 not /dev/md1" message?
> >> Some logical volumes are virtual disks vor kvm guests. Are these
> >> guests using sda only and not the mdraid?
> > 
> > Markus,
> > 
> > I see /etc/lvm/lvm.conf has an option to ignore md members and seems on 
> > by default in EL6:
> > md_component_detection = 1
> 
> This is a CentOS 5, but it also has this in lvm.conf, and it's value is 1.

from man lvm.conf
---
md_component_detection  — If set to 1, LVM2 will ignore
              devices  used  as  components  of  software  RAID  (md)
              devices  by  looking  for  md superblocks. This doesn’t
              always work satisfactorily e.g. if a  device  has  been
              reused without wiping the md superblocks first.
---

> > 
> > If you run "pvdisplay /dev/sda2" what does it show? Normally you should 
> > get a "Failed to read physical volume "/dev/sda2".
> 
> # pvs /dev/md1
>   Found duplicate PV b79x0kLXR9mAC0z0IZUxyJG1VC24Crl7: using /dev/sda2 not /dev/md1
>   PV         VG     Fmt  Attr PSize PFree  
>   /dev/sda2  vg_sys lvm2 a--  1.36T 553.16G
> 
> # pvs /dev/sda2
>   Found duplicate PV b79x0kLXR9mAC0z0IZUxyJG1VC24Crl7: using /dev/md1 not /dev/sda2
>   PV         VG     Fmt  Attr PSize PFree  
>   /dev/md1   vg_sys lvm2 a--  1.36T 553.16G
> 
> > ADditionally you can 
> > force a filter on the drives, smth like:
> > filter = ["r|/dev/sda2"]
> 
> I might try that, but it is not necessary on other machines with the same setup.
> It was not necessary on *this* machine (running since several years)

I've seen this problem on two machines (It came after some update on CentOS 5 )

you can set filter more strict to avoid bad detection
filter = [ "a/.*/" , "r|/dev/md.*|" ]

Pavel

-- 
Pavel Lisy <pavel.lisy at gmail.com>