[DRBD-user] BAD! BarrierAck received - please help

Philipp Herz - Profihost AG p.herz at profihost.ag
Fri Feb 21 14:37:35 CET 2014

Note: "permalinks" may not be as permanent as we would like,
direct links of old sources may well be a few messages off.

Hi everybody,

on a single-primary setup the master looses connection to slave system 
from time to time. It always complains about "bad barrier" like

dmesg (primary)
[181517.023255] d-con sda4: BAD! BarrierAck #1001121 received, expected 
[181517.093355] d-con sda4: peer( Secondary -> Unknown ) conn( Connected 
-> ProtocolError ) pdsk( UpToDate -> DUnknown )

After that drbd reconnects automatically and goes back to 
up2date/up2date state again.

We have checked everything like mainboard bios, nic firmware, different 
nics, cables and settings without any change to the behavior.

Both systems are running Kernel 3.10.30+67-ph and drbd module version 
8.4.3 and use drbd.conf below.

Please shed some light what else could cause "bad barrier" messages.

Maybe there is anyhing wrong with the current drbd.conf?

Thanks in advance,


global {
   usage-count no;

resource "sda4" {
   protocol B;

   handlers {
     pri-on-incon-degr "echo o > /proc/sysrq-trigger ; halt -f";
     pri-lost-after-sb "echo o > /proc/sysrq-trigger ; halt -f";
     local-io-error "echo o > /proc/sysrq-trigger ; halt -f";

   startup {
     degr-wfc-timeout 120;
     wfc-timeout 300;

   disk {
     on-io-error   call-local-io-error;

   net {
     max-buffers 8000;
     max-epoch-size 8000;
     unplug-watermark 2048;

     # auto-detect sndbuf-size
     sndbuf-size 0;

     after-sb-0pri discard-older-primary;
     after-sb-1pri discard-secondary;
     after-sb-2pri disconnect;
     rr-conflict call-pri-lost;

   syncer {
     rate 500M;
     al-extents 2539;

   on master {
     device     /dev/drbd0;
     disk       /dev/disk/by-id/scsi-SAdaptec_RAID1_SSD_SATA_154A0228-part4;
     meta-disk  internal;

   on slave {
     device     /dev/drbd0;
     disk       /dev/disk/by-id/scsi-SAdaptec_RAID1_SSD_SATA_47B792A8-part4;
     meta-disk  internal;


Mit freundlichen Grüßen
   Philipp Herz
Ihr Profihost Team


Profihost AG
Am Mittelfelde 29
30519 Hannover

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