[systemd-devel] 'udevadm settle' brakes lvm on top of imsm raid

[Oleg Samarin]

Thanks,

I made more debbuging with LVM and I realised, that lvm always uses the
last device it has scanned. Scanning of devices is called by udev rules
using "lvm pvscan --cache <device>" command. So the reason of using
/dev/sdb2 instead of /dev/md126p2 is that udev runs lvm in the following
order:
1. lvm pvscan --cash /dev/md126p2
2. lvm pvscan --cash /dev/sda2
3. lvm pvscan --cash /dev/sdb2

But there were no  /dev/sda2 and /dev/sdb2 before running anaconda at all.

[root at localhost ~]# ls -ld /dev/md* /dev/sd*
drwxr-xr-x. 2 root root      120 May 29 03:43 /dev/md
brw-rw----. 1 root disk   9, 126 May 29 03:43 /dev/md126
brw-rw----. 1 root disk 259,   0 May 29 03:43 /dev/md126p1
brw-rw----. 1 root disk 259,   1 May 29 03:43 /dev/md126p2
brw-rw----. 1 root disk   9, 127 May 29 03:43 /dev/md127
brw-rw----. 1 root disk   8,   0 May 29 03:43 /dev/sda
brw-rw----. 1 root disk   8,  16 May 29 03:43 /dev/sdb
brw-rw----. 1 root disk   8,  32 May 29 03:43 /dev/sdc
brw-rw----. 1 root disk   8,  33 May 29 03:43 /dev/sdc1
brw-rw----. 1 root disk   8,  34 May 29 03:43 /dev/sdc2
brw-rw----. 1 root disk   8,  48 May 29 03:43 /dev/sdd
brw-rw----. 1 root disk   8,  49 May 29 03:43 /dev/sdd1
brw-rw----. 1 root disk   8,  50 May 29 03:43 /dev/sdd2
brw-rw----. 1 root disk   8,  64 May 29 03:43 /dev/sde

They appear only after launching anaconda:

[root at localhost ~]# ls -ld /dev/md* /dev/sd*
drwxr-xr-x. 2 root root      120 May 29 03:47 /dev/md
brw-rw----. 1 root disk   9, 126 May 29 03:47 /dev/md126
brw-rw----. 1 root disk 259,   2 May 29 03:47 /dev/md126p1
brw-rw----. 1 root disk 259,   3 May 29 03:47 /dev/md126p2
brw-rw----. 1 root disk   9, 127 May 29 03:46 /dev/md127
brw-rw----. 1 root disk   8,   0 May 29 03:47 /dev/sda
brw-rw----. 1 root disk   8,   1 May 29 03:47 /dev/sda1
brw-rw----. 1 root disk   8,   2 May 29 03:47 /dev/sda2
brw-rw----. 1 root disk   8,  16 May 29 03:47 /dev/sdb
brw-rw----. 1 root disk   8,  17 May 29 03:47 /dev/sdb1
brw-rw----. 1 root disk   8,  18 May 29 03:47 /dev/sdb2
brw-rw----. 1 root disk   8,  32 May 29 03:46 /dev/sdc
brw-rw----. 1 root disk   8,  33 May 29 03:46 /dev/sdc1
brw-rw----. 1 root disk   8,  34 May 29 03:46 /dev/sdc2
brw-rw----. 1 root disk   8,  48 May 29 03:47 /dev/sdd
brw-rw----. 1 root disk   8,  49 May 29 03:47 /dev/sdd1
brw-rw----. 1 root disk   8,  50 May 29 03:47 /dev/sdd2
brw-rw----. 1 root disk   8,  64 May 29 03:47 /dev/sde

So the root problem is not in lvm. The root problem is why devices
"/sd[ab]?" appear? They shoud not exist because of /dev/sd[ab] are parts of
/dev/md126 raid.

I'm not insist that 'udevadm --settle' is the reason. But where should I
make future research?



2015-05-28 13:06 GMT+03:00 Lennart Poettering <lennart at poettering.net>:

> On Thu, 28.05.15 11:10, Oleg Samarin (osamarin68 at gmail.com) wrote:
>
> > Hi!
> >
> > I have an imsm raid-1 device /dev/md126 assembled of /dev/sda and
> /dev/sdb.
> > I have a lvm group on top of /dev/md126p2 with some logical volumes. All
> > this work fine with Fedora 21.
> >
> > I'm trying to fresh install Fedora 22 in some of lvm logical volume. I
> boot
> > with Fedora USB live media and run "Install to hard disk". But anaconda
> > does not see any existing lvm volumes so I can not choose them as a
> > destination.
>
> Please ask LVM people for help on this, the systemd mailing list is
> really not the right forum for this.
>
> Thanks,
>
> Lennart
>
> --
> Lennart Poettering, Red Hat
>
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