Monday, April 23, 2012

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

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