[linux-lvm] LVM filter ignored?

Zdenek Kabelac zkabelac at redhat.com
Mon Jan 2 15:06:05 UTC 2017

Dne 29.12.2016 v 21:28 knebb at knebb.de napsal(a):
> Hi all,
> I am using LVM for several years but now I face an issue where I have no clue
> how to deal with.
> I want to have a VG on top of a drbd device (Distributed Replicated Block
> Device) which should not be an issue according to docs:
> https://www.drbd.org/en/doc/users-guide-83/s-lvm-drbd-as-pv
> Unfortunately I am always getting "duplicate device" errors as LVM recons a pv
> on /dev/sdb (underlying device for drbd) as well as on /dev/drbd0
> Now I tried to configure filters to match my setup. But it seems I do not
> understand the filter rules.
> I need to enable /dev/sda incl. all partitions. (for root)
> I need to disable /dev/sdb at all as it is the device for drbd!
> I need to enable /dev/drbd0 as the "real" PV.
> I can disable all others.
> So I tried:
> filter = [ "r|sdb.*/|","a|drbd0/|","a|.*/|" ]


Just check the 'comment' for filters in lvm.conf -
there is stated you should NOT mix  'r' & 'a' together
(there is even no need for this in 99.9999%)

So please focus on keeping things simple:

- either use plain list of rejects  'r'
- or set 'white-list' with all 'a'  finished with 'r .*'

Every other usage does require quite good understanding how
the devices are scanned and how many accessible paths for them
exists in today's /dev directory.

To to be exact in your case:

Use just:    [ "r|/dev/sdb|" ]

OR  (if you want to use just drdb0) :

[ "a|drbd0/|", "r|.*/|" ]

(eventually add more 'a' with more PV devices you have)



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