Comment # 6 on bug 898913 from Liuhua Wang

(In reply to Werner Flamme from comment #5)
> It has been quite a while since I opened this bug case, 
Sorry for late.

> # rpm -qi device-mapper
> Name        : device-mapper
> Version     : 1.02.92
> Release     : 170.1
> Architecture: x86_64
> Install Date: Wed Jan 14 07:16:36 2015
> [...]
> Distribution: systemsmanagement / openSUSE_Factory
> 
> After connecting the USB disk:
> # lang=C fdisk -l
> 
> Disk /dev/sda: 238.5 GiB, 256060514304 bytes, 500118192 sectors
> Units: sectors of 1 * 512 = 512 bytes
> Sector size (logical/physical): 512 bytes / 512 bytes
> I/O size (minimum/optimal): 512 bytes / 512 bytes
> Disklabel type: dos
> Disk identifier: 0x00094dd6
> 
> Device     Boot     Start       End   Sectors   Size Id Type
> /dev/sda1            2048   4208639   4206592     2G 82 Linux swap / Solaris
> /dev/sda2  *      4208640 171976703 167768064    80G 83 Linux
> /dev/sda3       171976704 500117503 328140800 156.5G 83 Linux
> 
> # partprobe
> # vgscan ; vgchange -ay
> File descriptor 8 (pipe:[48944]) leaked on vgscan invocation. Parent PID
> 9788: bash
>   WARNING: lvmetad is running but disabled. Restart lvmetad before enabling
> it!
The lvm2-lvmetad is a metadata cache daemon. You can also use traditional way
to deal with metadata.
The warning messages are noisy but actually harmless. That is because you
disabled lvmetad(use_lvmetad=0) but the lvmetad daemon is running. In this
occasion lvmetad will not be used. Why the daemon is running, it is because
lvm2 package updating will 'try-restart lvm2-lvmetad.socket', which will start
lvm2-lvmetad.service, which is a feature of systemd. 
There are two ways to avoid the warning messages:
1. stop .service manually.
2. enable lvmetad by set use_lvmetad=1 in /etc/lvm/lvm.conf


> The warning texts are gone, but the volume groups on an external disk (USB3)
> are still not recognized. In fact, I often need the partprobe command to
> have the system recognize the disk (typically /dev/sdb) at all. And I do not
> know what to do about the lvmetad warning.
You mean if you not excute partprobe, lv cannot be activated?  Then please
provide the logs:
1. lsblk
2. cat /etc/fstab
3. pvs
4. lvs
5. lvmdump

Thanks!