Re: Different file in two bricks, no split-brain detected

["Chaloulos, Klearchos (Nokia - GR/Athens)" <klearchos.chaloulos@xxxxxxxxx>]

Hello,

 

I managed to get logs from two occurrences, please see anonymized logs attached.

 

Occurrence1: The copied file in both bricks had the correct checksum, but the client so an erroneous checksum.

Occurrence2: The copied file in one brick had the correct checksum and in the second brick has an erroneous checksum.

 

For details check the notes.txt file in the tarballs.

 

Do you have any idea what could be causing this behavior?

 

Best regards,

 

Klearchos

 

 

From: Chaloulos, Klearchos (Nokia - GR/Athens)
Sent: Monday, February 01, 2016 10:39 AM
To: 'EXT Krutika Dhananjay' <kdhananj@xxxxxxxxxx>
Cc: gluster-users@xxxxxxxxxxx
Subject: RE: [Gluster-users] Different file in two bricks, no split-brain detected

 

Hello,

 

Sorry for not replying, but lately the issue cannot be reproduced. If we have any new occurrences I’ll collect the logs and send them here.

 

Klearchos

 

From: EXT Krutika Dhananjay [mailto:kdhananj@xxxxxxxxxx]
Sent: Wednesday, January 27, 2016 7:12 AM
To: Chaloulos, Klearchos (Nokia - GR/Athens) <klearchos.chaloulos@xxxxxxxxx>
Cc: gluster-users@xxxxxxxxxxx
Subject: Re: [Gluster-users] Different file in two bricks, no split-brain detected

 

Hi,

 

Could you share the following pieces of information:

 

1) output of `gluster volume info <VOL>`

2) the client/mount logs

3) glustershd logs

 

-Krutika

 

---

From: "Klearchos Chaloulos (Nokia - GR/Athens)" <klearchos.chaloulos@xxxxxxxxx>
To: gluster-users@xxxxxxxxxxx
Sent: Tuesday, January 26, 2016 9:57:38 PM
Subject: [Gluster-users] Different file in two bricks,        no split-brain detected

 

Description of problem:

My setup has 5 gluster volumes, and each of them has 2 bricks as backend.

When I copy a large file (100MB) in a gluster volume, 9/10 times it works OK. But about 1 in 10 times the resulting md5 is wrong. After checking I found that the file in one brick has the correct md5sum, while the file in the other brick has a wrong md5sum. The size of the two files is the same.

By running "cmp -l <correct_file> <wrong_file>"

I found that the difference was in 49 bytes. So the files in the two bricks had the same size, but 49 files were different. Interestingly enough I saw the same number of 49 bytes being different at every check that I made.

 

Do you know what might cause this behavior, has anyone seen something like this before? Is this a bug in glusterfs?

 

 

Version-Release number of selected component (if applicable):

glusterfs 3.7.5 built on Nov 19 2015 16:29:59

Repository revision: git://git.gluster.com/glusterfs.git

Copyright (c) 2006-2011 Gluster Inc. <http://www.gluster.com>

GlusterFS comes with ABSOLUTELY NO WARRANTY.

You may redistribute copies of GlusterFS under the terms of the GNU General Public License.

 

 

How reproducible:

Not easy to reproduce, about 1 in 10 times in some environments, not reproducible at all in other environments.

 

Steps to Reproduce:

1. scp <100MB file> <path in gluster volume>

 

Actual results:

1. md5sum of destination should be the same as the source

2. If checksum of files is different between the two bricks, the command "gluster volume heal <vol-name> info split-brain" should return that the two bricks are in split-brain.

 

 

Expected results:

1. 1 in 10 times the destination file has incorrect checksum. Size is the same, but 49 bytes are altered.

2. "gluster volume heal <vol-name> info split-brain" does not return that the bricks are in split-brain, even though the checksum of the file in the two bricks is different. The size of the file is the same in the two bricks. But 49 bytes are altered.

 

Additional info:

 

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Attachment: occurence2.tgz
Description: occurence2.tgz

Attachment: occurence1.tgz
Description: occurence1.tgz

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