Hi,

When I install the latest drbd-utils and attempt to configure a drbd
device using a version 9 feature (e.g. more than 2 nodes), it fails to
work:

# drbdadm adjust all
/etc/drbd.d/your_resource.res:1: in resource your_resource:
        There are multiple host sections for the peer node.
        Use the --peer option to select which peer section to use.
No valid meta data found


I then noticed that the loaded drbd module is not 9 but 8.4.11 from
linux-images:

# modinfo drbd
filename:       /lib/modules/5.10.0-10-amd64/kernel/drivers/block/drbd/drbd.ko
alias:          block-major-147-*
license:        GPL
version:        *8.4.11*
description:    drbd - Distributed Replicated Block Device *v8.4.11*
vermagic:       5.10.0-10-amd64 SMP mod_unload modversions

# dpkg-query -S /lib/modules/5.10.0-10-amd64/kernel/drivers/block/drbd/drbd.ko
linux-image-5.10.0-10-amd64:
/lib/modules/5.10.0-10-amd64/kernel/drivers/block/drbd/drbd.ko

I would guess that either linux-image or drbd-utils packages need to
be updated to include and reference a newer module (drbd9.ko)?

I don't think drbd9 kernel module is currently included in Debian, so
you would need to build it yourself or use packages provided by LINBIT.