[linux-lvm] "Unknown feature in status" message when running lvs/lvdisplay against cached LVs

Gang He GHe at suse.com
Wed Jul 10 06:20:20 UTC 2019

Hi Marian,

Thank for your helps, the patch is effective to fix this error message.


-----Original Message-----
From: Marian Csontos [mailto:mcsontos at redhat.com] 
Sent: 2019年7月8日 16:37
To: LVM general discussion and development <linux-lvm at redhat.com>; Gang He <GHe at suse.com>
Subject: Re: [linux-lvm] "Unknown feature in status" message when running lvs/lvdisplay against cached LVs

On 7/5/19 11:20 AM, Gang He wrote:
> Hi Guys,
> I uses lvm2-2.02.180, I got an error message when running lvs/lvdisplay against cached LVs.
> e.g.
> linux-v5ay:~ # lvs
>    Unknown feature in status: 8 1324/8192 128 341/654272 129 151 225 1644 0 341 0 3 metadata2 writethrough no_discard_passdown 2 migration_threshold 2048 smq 0 rw -
>    LV   VG     Attr       LSize  Pool       Origin       Data%  Meta%  Move Log Cpy%Sync Convert
>    home system -wi-ao---- 17.99g
>    root system Cwi-aoC--- 20.00g [lvc_root] [root_corig] 0.05   16.16           0.00
>    swap system -wi-ao----  2.00g

You need this patch:


Kernel introduced a new feature which is not recognized by lvm versions released before the kernel (which is anything up to latest 2.02.185). 
This will be included in the next lvm release.

-- Marian

> The bug can be reproduced stably with the below steps.
> Have a (virtual) machine with 2 disk drives Install os with LVM as 
> root volume Then, add the second disk after os is installed.
> # pvcreate /dev/sdb
> # vgextend system /dev/sdb
> # lvcreate --type cache-pool -l 100%FREE -n lvc_root system /dev/sdb # 
> lvconvert --type cache --cachepool system/lvc_root system/root then 
> run `lvs` or `lvdisplay` command to trigger the issue
> Thanks
> Gang
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