Re: [Gluster-devel] Query on healing process

[Ravishankar N <ravishankar@xxxxxxxxxx>]

On 03/04/2016 12:10 PM, ABHISHEK PALIWAL wrote:

Hi Ravi,

3. On the rebooted node, do you have ssl enabled by any chance? There is a bug for "Not able to fetch volfile' when ssl is enabled: https://bugzilla.redhat.com/show_bug.cgi?id=1258931

->>>>> I have checked but ssl is disabled but still getting these errors

# gluster volume heal c_glusterfs info
c_glusterfs: Not able to fetch volfile from glusterd
Volume heal failed.

Ok, just to confirm, glusterd  and other brick processes are running after this node rebooted? 
When you run the above command, you need to check /var/log/glusterfs/glfsheal-volname.log logs errros. Setting client-log-level to DEBUG would give you a more verbose message

# gluster volume heal c_glusterfs info split-brain
c_glusterfs: Not able to fetch volfile from glusterd
Volume heal failed.

And based on the your observation I understood that this is not the problem of split-brain but is there any way through which can find out the file which is not in split-brain as well as not in sync?

`gluster volume heal c_glusterfs info split-brain`  should give you files that need heal.

# getfattr -m . -d -e hex /opt/lvmdir/c2/brick/logfiles/availability/CELLO_AVAILABILITY2_LOG.xml
getfattr: Removing leading '/' from absolute path names
# file: opt/lvmdir/c2/brick/logfiles/availability/CELLO_AVAILABILITY2_LOG.xml
trusted.afr.c_glusterfs-client-0=0x000000000000000000000000
trusted.afr.c_glusterfs-client-2=0x000000000000000000000000
trusted.afr.c_glusterfs-client-4=0x000000000000000000000000
trusted.afr.c_glusterfs-client-6=0x000000000000000000000000
trusted.afr.c_glusterfs-client-8=0x000000060000000000000000 //because client8 is the latest client in our case and starting 8 digits

00000006....are saying like there is something in changelog data.

trusted.afr.dirty=0x000000000000000000000000
trusted.bit-rot.version=0x000000000000001356d86c0c000217fd
trusted.gfid=0x9f5e354ecfda40149ddce7d5ffe760ae

# lhsh 002500 getfattr -m . -d -e hex /opt/lvmdir/c2/brick/logfiles/availability/CELLO_AVAILABILITY2_LOG.xml
getfattr: Removing leading '/' from absolute path names
# file: opt/lvmdir/c2/brick/logfiles/availability/CELLO_AVAILABILITY2_LOG.xml
trusted.afr.c_glusterfs-client-1=0x000000000000000000000000 // and here we can say that there is no split brain but the file is out of sync
trusted.afr.dirty=0x000000000000000000000000
trusted.bit-rot.version=0x000000000000001156d86c290005735c
trusted.gfid=0x9f5e354ecfda40149ddce7d5ffe760ae

# gluster volume info
 
Volume Name: c_glusterfs
Type: Replicate
Volume ID: c6a61455-d378-48bf-ad40-7a3ce897fc9c
Status: Started
Number of Bricks: 1 x 2 = 2
Transport-type: tcp
Bricks:
Brick1: 10.32.0.48:/opt/lvmdir/c2/brick
Brick2: 10.32.1.144:/opt/lvmdir/c2/brick
Options Reconfigured:
performance.readdir-ahead: on
network.ping-timeout: 4
nfs.disable: on


# gluster volume info                  
 
Volume Name: c_glusterfs
Type: Replicate
Volume ID: c6a61455-d378-48bf-ad40-7a3ce897fc9c
Status: Started
Number of Bricks: 1 x 2 = 2
Transport-type: tcp
Bricks:
Brick1: 10.32.0.48:/opt/lvmdir/c2/brick
Brick2: 10.32.1.144:/opt/lvmdir/c2/brick
Options Reconfigured:
performance.readdir-ahead: on
network.ping-timeout: 4
nfs.disable: on

# gluster --version
glusterfs 3.7.8 built on Feb 17 2016 07:49:49
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.
# gluster volume heal info heal-failed
Usage: volume heal <VOLNAME> [enable | disable | full |statistics [heal-count [replica <HOSTNAME:BRICKNAME>]] |info [healed | heal-failed | split-brain] |split-brain {bigger-file <FILE> |source-brick <HOSTNAME:BRICKNAME> [<FILE>]}]
# gluster volume heal c_glusterfs info heal-failed
Command not supported. Please use "gluster volume heal c_glusterfs info" and logs to find the heal information.
# lhsh 002500
 _______  _____   _____              _____ __   _ _     _ _     _
 |       |_____] |_____]      |        |   | \  | |     |  \___/
 |_____  |       |            |_____ __|__ |  \_| |_____| _/   \_

002500> gluster --version
glusterfs 3.7.8 built on Feb 17 2016 07:49:49
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.
002500>

Regards,

Abhishek

On Thu, Mar 3, 2016 at 4:54 PM, ABHISHEK PALIWAL <abhishpaliwal@xxxxxxxxx> wrote:

On Thu, Mar 3, 2016 at 4:10 PM, Ravishankar N <ravishankar@xxxxxxxxxx> wrote:

Hi,

On 03/03/2016 11:14 AM, ABHISHEK PALIWAL wrote:

Hi Ravi,

As I discussed earlier this issue, I investigated this issue and find that healing is not triggered because the "gluster volume heal c_glusterfs info split-brain" command not showing any entries as a outcome of this command even though the file in split brain case.

Couple of observations from the 'commands_output' file.

getfattr -d -m . -e hex opt/lvmdir/c2/brick/logfiles/availability/CELLO_AVAILABILITY2_LOG.xml
The afr xattrs do not indicate that the file is in split brain:
# file: opt/lvmdir/c2/brick/logfiles/availability/CELLO_AVAILABILITY2_LOG.xml
trusted.afr.c_glusterfs-client-1=0x000000000000000000000000
trusted.afr.dirty=0x000000000000000000000000
trusted.bit-rot.version=0x000000000000000b56d6dd1d000ec7a9
trusted.gfid=0x9f5e354ecfda40149ddce7d5ffe760ae



getfattr -d -m . -e hex opt/lvmdir/c2/brick/logfiles/availability/CELLO_AVAILABILITY2_LOG.xml
trusted.afr.c_glusterfs-client-0=0x000000080000000000000000
trusted.afr.c_glusterfs-client-2=0x000000020000000000000000
trusted.afr.c_glusterfs-client-4=0x000000020000000000000000
trusted.afr.c_glusterfs-client-6=0x000000020000000000000000
trusted.afr.dirty=0x000000000000000000000000
trusted.bit-rot.version=0x000000000000000b56d6dcb7000c87e7
trusted.gfid=0x9f5e354ecfda40149ddce7d5ffe760ae

1. There doesn't seem to be a split-brain going by the trusted.afr* xattrs.

if it is not the split brain problem then how can I resolve this.
 

2. You seem to have re-used the bricks from another volume/setup. For replica 2, only trusted.afr.c_glusterfs-client-0 and trusted.afr.c_glusterfs-client-1 must be present but I see 4 xattrs - client-0,2,4 and 6

could you please suggest why these entries are there because I am not able to find out scenario. I am rebooting the one board multiple times to reproduce the issue and after every reboot doing the remove-brick and add-brick on the same volume for the second board.
 

3. On the rebooted node, do you have ssl enabled by any chance? There is a bug for "Not able to fetch volfile' when ssl is enabled: https://bugzilla.redhat.com/show_bug.cgi?id=1258931

Btw, you for data and metadata split-brains you can use the gluster CLI  https://github.com/gluster/glusterfs-specs/blob/master/done/Features/heal-info-and-split-brain-resolution.md instead of modifying the file from the back end.

But you are saying it is not split brain problem and even the split-brain command  is not showing any file so how can I find the bigger file in size. Also in my case the file size is fix 2MB it is overwritten every time. 

-Ravi

So, what I have done I manually deleted the gfid entry of that file from .glusterfs directory and follow the instruction mentioned in the following link to do heal

https://github.com/gluster/glusterfs/blob/master/doc/debugging/split-brain.md

and this works fine for me.

But my question is why the split-brain command not showing any file in output.

Here I am attaching all the log which I get from the node for you and also the output of commands from both of the boards

In this tar file two directories are present

000300 - log for the board which is running continuously

002500-  log for the board which is rebooted

I am waiting for your reply please help me out on this issue.

Thanks in advanced.

Regards,

Abhishek

On Fri, Feb 26, 2016 at 1:21 PM, ABHISHEK PALIWAL <abhishpaliwal@xxxxxxxxx> wrote:

On Fri, Feb 26, 2016 at 10:28 AM, Ravishankar N <ravishankar@xxxxxxxxxx> wrote:

On 02/26/2016 10:10 AM, ABHISHEK PALIWAL wrote:

Yes correct

Okay, so when you say the files are not in sync until some time, are you getting stale data when accessing from the mount?
I'm not able to figure out why heal info shows zero when the files are not in sync, despite all IO happening from the mounts. Could you provide the output of getfattr -d -m . -e hex /brick/file-name from both bricks when you hit this issue?

I'll provide the logs once I get. here delay means we are powering on the second board after the 10 minutes.

On Feb 26, 2016 9:57 AM, "Ravishankar N" <ravishankar@xxxxxxxxxx> wrote:

Hello,

On 02/26/2016 08:29 AM, ABHISHEK PALIWAL wrote:

Hi Ravi,

Thanks for the response.

We are using Glugsterfs-3.7.8

Here is the use case:

We have a logging file which saves logs of the events for every board of a node and these files are in sync using glusterfs. System in replica 2 mode it means When one brick in a replicated volume goes offline, the glusterd daemons on the other nodes keep track of all the files that are not replicated to the offline brick. When the offline brick becomes available again, the cluster initiates a healing process, replicating the updated files to that brick. But in our casse, we see that log file of one board is not in the sync and its format is corrupted means files are not in sync.

Just to understand you correctly, you have mounted the 2 node replica-2 volume on both these nodes and writing to a logging file from the mounts right?

Even the outcome of #gluster volume heal c_glusterfs info shows that there is no pending heals.

Also , The logging file which is updated is of fixed size and the new entries will be wrapped ,overwriting the old entries.

This way we have seen that after few restarts , the contents of the same file on two bricks are different , but the volume heal info shows zero entries

Solution:

But when we tried to put delay  > 5 min before the healing everything is working fine.

Regards,

Abhishek

On Fri, Feb 26, 2016 at 6:35 AM, Ravishankar N <ravishankar@xxxxxxxxxx> wrote:

On 02/25/2016 06:01 PM, ABHISHEK PALIWAL wrote:

Hi,

Here, I have one query regarding the time taken by the healing process.

In current two node setup when we rebooted one node then the self-healing process starts less than 5min interval on the board which resulting the corruption of the some files data.

Heal should start immediately after the brick process comes up. What version of gluster are you using? What do you mean by corruption of data? Also, how did you observe that the heal started after 5 minutes?
-Ravi

And to resolve it I have search on google and found the following link:
https://support.rackspace.com/how-to/glusterfs-troubleshooting/

Mentioning that the healing process can takes upto 10min of time to start this process.

Here is the statement from the link:

"Healing replicated volumes

When any brick in a replicated volume goes offline, the glusterd daemons on the remaining nodes keep track of all the files that are not replicated to the offline brick. When the offline brick becomes available again, the cluster initiates a healing process, replicating the updated files to that brick. The start of this process can take up to 10 minutes, based on observation."

After giving the time of more than 5 min file corruption problem has been resolved.

So, Here my question is there any way through which we can reduce the time taken by the healing process to start?

Regards,
Abhishek Paliwal

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Abhishek Paliwal

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