Bug#870692: lvm2: LVM on dmraid fails after upgrade to stretch 9.1

[Over Dexia]

Package: lvm2
Version: 2.02.168-2
Severity: normal

Upgraded from jessie to stretch via apt.

Boot drops to initramfs prompt after LVM error messages:

...
Cannot activate LVs in VG fw03-vg while PVs appear on duplicate devices.
Gave up waiting for root file system device. Common problems:
...
(initramfs)

dmraid looks OK, modules are there, partitions active. The /dev/dm-?
-devices are present. The error messages before can be reproduced by:

(initramfs) vgchange -ay

WARNING: Failed to connect to lvmetad. Falling back to device scanning.
WARNING: PV xyz on /dev/sda5 was already found on
/dev/disk/by-id/dm-name-xyz
WARNING: PV xyz on /dev/sdb5 was already found on
/dev/disk/by-id/dm-name-xyz
WARNING: PV xyz prefers device /dev/disk/by-id/dm-name-xyz because
device is in dm subsystem.
WARNING: PV xyz prefers device /dev/disk/by-id/dm-name-xyz because
device is in dm subsystem.
Cannot activate LVs in VG fw03-vg while PVs appear on duplicate devices.
...3 more times
Cannot activate LVs in VG fw03-vg while PVs appear on duplicate devices.
0 logical volume(s) in volume group "fw03-vg" now active

Given the dmraid, the duplicate PVs are expected...?

When I do a
dmraid -Z -ay
to suppress the /dev/sd<x> devices
everything is fine on vgchange -ay and I can exit to boot.

lvm2 2.02.133-1ub from a Ubuntu DVD works without issues.
The former jessie lvm2 2.02.111-2.2 also worked.

I suspect the check for duplicate PVs is new and doesn't cooperate well
with the dmraid ... somehow one would have to change the dmraid
initialisation in the initrd, or the lvm method of device scanning.

Kernel is 4.9.0-3-amd64 #1 SMP Debian 4.9.30-2+deb9u2 x86_64
Systems are Fujitsu Siemens RX100 S4 and RX100 S5
Adapters are LSI MegaRAID SATA RAID.

I'm happy to help with further info as good as I can. Just ask, I'll try.

Regards, jo