Доброго времени суток, есть две машины xen0 (192.168.1.8) и xen1 (192.168.1.9).
Установил на обе drbd модуль и sys-cluster/drbd-8.0.11.
Gentoo Linux, ARCH amd64

Linux xen1 2.6.18-xen0 #4 SMP Thu Jun 19 09:55:46 YEKST 2008 x86_64 Intel(R) Pentium(R) Dual  CPU  E2180  @ 2.00GHz GenuineIntel GNU/Linux

xen1 mnt # lsmod
Module                  Size  Used by
drbd                  227112  1

xen1 mnt # cat /etc/make.conf
# These settings were set by the catalyst build script that automatically
# built this stage.
# Please consult /etc/make.conf.example for a more detailed example.
CFLAGS="-O2 -pipe"
CXXFLAGS="${CFLAGS}"
# This should not be changed unless you know exactly what you are doing.  You
# should probably be using a different stage, instead.
CHOST="x86_64-pc-linux-gnu"
VIDEO_CARDS="i810"
INPUT_DEVICES="keyboard mouse"

Отредактировал конфигурационный файл:

xen1 mnt # cat /etc/drbd.conf
resource drbd0 {
protocol C;

startup {
degr-wfc-timeout 120;    # 2 minutes.
become-primary-on both;
}

disk {
on-io-error   detach;
}

syncer {
rate 5M;
}

net {
ping-int 10;
max-buffers 2048;
max-epoch-size 2048;
allow-two-primaries;
#after-sb-0pri discard-younger-primary;
#after-sb-1pri consensus;
}

  on xen1 {
       device /dev/drbd0;
       disk /dev/sdb2;
       address 192.168.1.9:7789;
#       meta-disk /dev/sdb1[1];
meta-disk internal;
}

  on xen0 {
       device /dev/drbd0;
       disk /dev/sda2;
       address 192.168.1.8:7789;
#       meta-disk /dev/sda1[1];
meta-disk internal;
        }

Создал meta данные, на обоих хостах (drbdadm create-md drbd0. Writing meta data...
New drbd meta data block sucessfully created.),запускаю drbd на xen0:
/etc/init.d/drbd start
drbd ожидает соединения...
запускаю drbd на xen1: * Starting DRBD resources:
*   Loading drbd module ...                                                                                                                  [ ok ]
*   Setting drbd parameters [ d0 s0 n0 ]                                                                                                     [ ok ]
*   Waiting for udev device creation ... ...                                                                                                 [ ok ]
*   Waiting for connection                                                                                                                   [ ok ]
xen1 mnt #
запускается и соединяется с xen0.
выполняю на xen0: drbdadm primary all, смотрю статус drbd:
xen0 etc # cat /proc/drbd
version: 8.2.6 (api:88/proto:86-88)
GIT-hash: 3e69822d3bb4920a8c1bfdf7d647169eba7d2eb4 build by root@xen0, 2008-06-20 14:23:42
0: cs:WFConnection st:Primary/Unknown ds:UpToDate/Inconsistent C r---
    ns:0 nr:0 dw:0 dr:0 al:0 bm:0 lo:0 pe:0 ua:0 ap:0 oos:77141736

смотрю стстус на xen1:xen1 mnt # cat /proc/drbd
version: 8.2.6 (api:88/proto:86-88)
GIT-hash: 3e69822d3bb4920a8c1bfdf7d647169eba7d2eb4 build by root@xen1.kzts.ru, 2008-06-19 10:03:32
0: cs:StandAlone st:Secondary/Unknown ds:Inconsistent/DUnknown   r---
    ns:0 nr:0 dw:0 dr:0 al:0 bm:0 lo:0 pe:0 ua:0 ap:0 oos:77141736
пробую подключиться:
xen1 mnt # drbdadm connect all
сразу же:
xen1 mnt # cat /proc/drbd
version: 8.2.6 (api:88/proto:86-88)
GIT-hash: 3e69822d3bb4920a8c1bfdf7d647169eba7d2eb4 build by root@xen1.kzts.ru, 2008-06-19 10:03:32
0: cs:WFBitMapT st:Secondary/Primary ds:Inconsistent/UpToDate C r---
    ns:0 nr:0 dw:0 dr:0 al:0 bm:0 lo:0 pe:0 ua:0 ap:0 oos:77141736
Через 1-2 секунды:
xen1 mnt # cat /proc/drbd
version: 8.2.6 (api:88/proto:86-88)
GIT-hash: 3e69822d3bb4920a8c1bfdf7d647169eba7d2eb4 build by root@xen1.kzts.ru, 2008-06-19 10:03:32
0: cs:StandAlone st:Secondary/Unknown ds:Inconsistent/DUnknown   r---
    ns:0 nr:0 dw:0 dr:0 al:0 bm:0 lo:0 pe:0 ua:0 ap:0 oos:77141736
лог:
Jun 25 14:55:48 xen1 drbd0: conn( StandAlone -> Unconnected )
Jun 25 14:55:48 xen1 drbd0: Starting receiver thread (from drbd0_worker [2278])
Jun 25 14:55:48 xen1 drbd0: receiver (re)started
Jun 25 14:55:48 xen1 drbd0: conn( Unconnected -> WFConnection )
Jun 25 14:55:48 xen1 drbd0: Handshake successful: Agreed network protocol version 88
Jun 25 14:55:48 xen1 drbd0: conn( WFConnection -> WFReportParams )
Jun 25 14:55:48 xen1 drbd0: Starting asender thread (from drbd0_receiver [2325])
Jun 25 14:55:48 xen1 drbd0: data-integrity-alg: <not-used>
Jun 25 14:55:48 xen1 drbd0: Becoming sync target due to disk states.
Jun 25 14:55:48 xen1 drbd0: peer( Unknown -> Primary ) conn( WFReportParams -> WFBitMapT ) pdsk( DUnknown -> UpToDate )
Jun 25 14:55:48 xen1 drbd0: Writing meta data super block now.
Jun 25 14:55:49 xen1 drbd0: conn( WFBitMapT -> WFSyncUUID )
Jun 25 14:55:49 xen1 drbd0: helper command: /sbin/drbdadm before-resync-target
Jun 25 14:55:49 xen1 drbd0: before-resync-target handler returned 3, dropping connection.
Jun 25 14:55:49 xen1 drbd0: peer( Primary -> Unknown ) conn( WFSyncUUID -> Disconnecting ) pdsk( UpToDate -> DUnknown )
Jun 25 14:55:49 xen1 drbd0: asender terminated
Jun 25 14:55:49 xen1 drbd0: Terminating asender thread
Jun 25 14:55:49 xen1 drbd0: Writing meta data super block now.
Jun 25 14:55:49 xen1 drbd0: tl_clear()
Jun 25 14:55:49 xen1 drbd0: Connection closed
Jun 25 14:55:49 xen1 drbd0: conn( Disconnecting -> StandAlone )
Jun 25 14:55:49 xen1 drbd0: receiver terminated
Jun 25 14:55:49 xen1 drbd0: Terminating receiver thread

Вопросы: Что значит строка "drbd0: before-resync-target handler returned 3, dropping connection?" В чём причина остановки синхронизации? Что нужно сделать что-бы drdb начал синхронизировать устройства?

Пробовал запускать drbd в режиме Primary\Secondary, такая же ошибка.