[Gluster-users] Need help in understanding volume heal-info behavior

[Ravishankar N]

On 04/28/2014 01:30 AM, Chalcogen wrote:
> Hi everyone,
>
> I have trouble understanding the following behavior:
>
> Suppose I have a replica 2 volume 'testvol' on two servers, server1 
> and server2, composed of server1:/bricks/testvol/brick and 
> server2:/bricks/testvol/brick. Also, suppose it contains a good number 
> of files.
>
> Now, assume I remove one of the two bricks, as:
>
> root at server1~# gluster volume remove-brick testvol replica 1 
> server1:/bricks/testvol/brick
>
> Now, I unmount and delete the logical volume supporting the brick and 
> then recreate it (with a different size), and mount it the same way as 
> it was mounted before (at /brick/testvol/). Then, I re-add it as:
>
> root at server1~# gluster volume add-brick testvol replica 2 
> server1:/bricks/testvol/brick
>
> I observe that the brick on server1 does not contain any of the data 
> that was in the volume.
>
> root at server1~# ls /bricks/testvol/brick
> root at server1~#
>
> This is all right by me, since glusterfs needs some time to discover 
> and sync files that are absent on the brick of server1. In fact, if I 
> leave the setup undisturbed for 15 minutes to half an hour, I find 
> that all data appears within the brick of server1, just as you would 
> expect. Also, if I wish to speed up the process, I simply do a ls -Ra 
> on the directory where the volume is mounted, and all files sync onto 
> server1's brick. This is also very much as expected.
>
> However, during the period where data on server1's brick is not 
> available, if you query the heal info for the volume, gluster cli 
> reports that 'Number of entries' is '0', and that too all of 'info', 
> 'heal-failed', and 'split-brain'. This is what becomes a bit of a 
> trouble for me. Fact is, we are attempting to automate the monitoring 
> of our glusterfs volumes, and we depend upon heal info alone to decide 
> whether data on server1 and server2 are in sync.
>
> Could somebody, therefore, help me with the following questions?
> a) Which files exactly show up in heal info?
The files which are healed either by the self-heal daemon or by the 
gluster heal commands.
> b) What exactly should I look to monitor if we are to ascertain that 
> data on our servers are in sync?
>
After adding a new replica brick, you need to run a full heal (gluster 
volume heal <vol-name> full). Then the results will show up in the heal 
info output.
> Thanks a lot for your responses!
>
> Anirban
>
> P.s. I am using glusterfs 3.4.2 over linux kernel version 2.6.34.
>
>
>
> _______________________________________________
> Gluster-users mailing list
> Gluster-users at gluster.org
> http://supercolony.gluster.org/mailman/listinfo/gluster-users

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://supercolony.gluster.org/pipermail/gluster-users/attachments/20140428/7e197fad/attachment.html>