JBD: Barrier-based Sync Failed On md0-8 – Disabling Barriers Error and Solution

I‘ve used the mdadm command line utility to setup and manage software RAID 6 under Debian Linux server. However, I get the following message in /var/log/messages file:
[ 14.003707] JBD: barrier-based sync failed on md0-8 – disabling barriers

How do I fix the message ‘JBD error message “barrier-based sync failed”‘?

This is not a problem. This is just an informational log entry in /var/log/messages. Use the following commands to see the current status of your raid:
# cat /proc/mdstat
Sample outputs:

Personalities : [raid6] [raid5] [raid4] 
md0 : active raid6 sda1[0] sde1[4] sdd1[3] sdc1[2] sdb1[1]
      125856768 blocks super 1.2 level 6, 512k chunk, algorithm 2 [5/5] [UUUUU]
      
unused devices: 

# mdadm -q -D /dev/md0
Sample outputs:

/dev/md0:
        Version : 1.2
  Creation Time : Sat Sep  3 00:46:50 2011
     Raid Level : raid6
     Array Size : 125856768 (120.03 GiB 128.88 GB)
  Used Dev Size : 41952256 (40.01 GiB 42.96 GB)
   Raid Devices : 5
  Total Devices : 5
    Persistence : Superblock is persistent

    Update Time : Mon Sep  5 02:41:30 2011
          State : clean
 Active Devices : 5
Working Devices : 5
 Failed Devices : 0
  Spare Devices : 0

         Layout : left-symmetric
     Chunk Size : 512K

           Name : nas01:0  (local to host nas01)
           UUID : 076f728e:4e89c5a7:dfc456ff:c12a1b22
         Events : 696

    Number   Major   Minor   RaidDevice State
       0       8        1        0      active sync   /dev/sda1
       1       8       17        1      active sync   /dev/sdb1
       2       8       33        2      active sync   /dev/sdc1
       3       8       49        3      active sync   /dev/sdd1
       4       8       65        4      active sync   /dev/sde1

How Do I Remove This Message?

Edit grub.conf or menu.lst and pass the following parameter to kernel:

 barrier=off 

More information is available here.

Posted by: SXI ADMIN

The author is the creator of SXI LLC and a seasoned sysadmin, DevOps engineer, and a trainer for the Linux operating system/Unix shell scripting. Get the latest tutorials on SysAdmin, Linux/Unix and open source topics via RSS/XML feed or weekly email newsletter.