barrier-based sync failed - disabling barriers

barrier-based sync failed - disabling barriers

[Gábor Lénárt]

Hi All,

I have a kernel log entry I've never seen before:

JBD: barrier-based sync failed on cciss!c0d0p3-8 - disabling barriers
JBD: barrier-based sync failed on cciss!c0d0p1-8 - disabling barriers

Should I worry? Can it be blamed for the poor I/O performance? How can I
solve this problem? Even if it doesn't mean too much (what I should
worry about), it's a bit annoying (as always) to see odd messages.

The ext4 filesystems were created by the installer of an older (ubuntu)
distribution, I guess, it can cause problems after the upgrade. Can I
convert/modify the filesystem (like with tune2fs) not to have these messages
and problem?

Thanks a lot in advance for anyone who has some suggestion.

Regards,

Gábor Lénárt

Re: barrier-based sync failed - disabling barriers

[Gábor Lénárt]

On Tue, Oct 18, 2011 at 10:11:59AM +0200, Gábor Lénárt wrote:
> I have a kernel log entry I've never seen before:
> 
> JBD: barrier-based sync failed on cciss!c0d0p3-8 - disabling barriers
> JBD: barrier-based sync failed on cciss!c0d0p1-8 - disabling barriers
> 
> Should I worry? Can it be blamed for the poor I/O performance? How can I
> solve this problem? Even if it doesn't mean too much (what I should
> worry about), it's a bit annoying (as always) to see odd messages.
> 
> The ext4 filesystems were created by the installer of an older (ubuntu)
> distribution, I guess, it can cause problems after the upgrade. Can I
> convert/modify the filesystem (like with tune2fs) not to have these
> messages and problem?


Sorry, I forgot to give some information:

Linux nopea1 2.6.32-34-server #77-Ubuntu SMP Tue Sep 13 20:54:38 UTC 2011 x86_64 GNU/Linux
Ubuntu 10.04.3 LTS "lucid"
Hardware name: ProLiant DL360 G5
/dev/cciss/c0d0: (Smart Array E200i) RAID 1 Volume 0 status: OK. 

Filesystem volume name:   /
Last mounted on:          /
Filesystem UUID:          06a107ec-cf2a-4dca-bb95-ab7745402f5b
Filesystem magic number:  0xEF53
Filesystem revision #:    1 (dynamic)
Filesystem features:      has_journal ext_attr resize_inode dir_index
filetype needs_recovery extent flex_bg sparse_super large_file huge_file
uninit_bg dir_nlink extra_isize
Filesystem flags:         signed_directory_hash 
Default mount options:    (none)
Filesystem state:         clean
Errors behavior:          Continue
Filesystem OS type:       Linux
Inode count:              610800
Block count:              2441876
Reserved block count:     0
Free blocks:              2079823
Free inodes:              577158
First block:              0
Block size:               4096
Fragment size:            4096
Reserved GDT blocks:      596
Blocks per group:         32768
Fragments per group:      32768
Inodes per group:         8144
Inode blocks per group:   509
Flex block group size:    16
Filesystem created:       Wed Oct 12 17:24:42 2011
Last mount time:          Tue Oct 18 10:01:29 2011
Last write time:          Wed Oct 12 19:39:53 2011
Mount count:              6
Maximum mount count:      35
Last checked:             Wed Oct 12 17:24:42 2011
Check interval:           15552000 (6 months)
Next check after:         Mon Apr  9 17:24:42 2012
Lifetime writes:          833 MB
Reserved blocks uid:      0 (user root)
Reserved blocks gid:      0 (group root)
First inode:              11
Inode size:               256
Required extra isize:     28
Desired extra isize:      28
Journal inode:            8
Default directory hash:   half_md4
Directory Hash Seed:      0914f7b2-bfa3-4718-811d-fc02c7361b32
Journal backup:           inode blocks
Journal features:         journal_incompat_revoke
Journal size:             128M
Journal length:           32768
Journal sequence:         0x0000055a
Journal start:            1


- Gábor

Re: barrier-based sync failed - disabling barriers

[Jan Kara]

  Hello,

On Tue 18-10-11 10:11:59, Gábor Lénárt wrote:
> I have a kernel log entry I've never seen before:
> 
> JBD: barrier-based sync failed on cciss!c0d0p3-8 - disabling barriers
> JBD: barrier-based sync failed on cciss!c0d0p1-8 - disabling barriers
> 
> Should I worry? Can it be blamed for the poor I/O performance? How can I
> solve this problem? Even if it doesn't mean too much (what I should
> worry about), it's a bit annoying (as always) to see odd messages.
> 
> The ext4 filesystems were created by the installer of an older (ubuntu)
> distribution, I guess, it can cause problems after the upgrade. Can I
> convert/modify the filesystem (like with tune2fs) not to have these messages
> and problem?
  You didn't choose the best list for this question -
linux-ext4@vger.kernel.org would be a better fit. LKML has far too big
traffic and things get lost... That's why I'm answering your email that
late as well.

  The messages about barriers are normal with the HW. They say that the
hardware (or the storage driver) does not support cache flush command.
Generally, if the array has battery backed write caches (or is otherwise
protected from power failure), you don't have to use barriers anyway (and
you can gain some performance boost by that). If you don't want to see
those messages in the log, use nobarrier mount option.

  These messages can only have positive effect on performance so if you
have some performance problems, it's something else...

								Honza