Gluster users - Apr 2017 - adding arbiter

As I understand it, only new files will be sharded, but simply renaming or
moving them may be enough in that case.

I'm interested in the arbiter/sharding bug you've mentioned. Could you
provide any more details or a link?

Cheers,
 D

On 30 March 2017 at 20:25, Laura Bailey <lbailey at redhat.com> wrote:
> I can't answer all of these, but I think the only way to share existing
> files is to create a new volume with sharding enabled and copy the files
> over into it.
>
> Cheers,
> Laura B
>
>
> On Friday, March 31, 2017, Alessandro Briosi <ab1 at metalit.com>
wrote:
>
>> Hi I need some advice.
>>
>> I'm currently on 3.8.10 and would like to know the following:
>>
>> 1. If I add an arbiter to an existing volume should I also run a
>> rebalance?
>> 2. If I had sharding enabled would adding the arbiter trigger the
>> corruption bug?
>> 3. What's the procedure to enable sharding on an existing volume so
that
>> it shards already existing files?
>> 4. Suppose I have sharding disabled, then add an arbiter brick, then
>> enable sharding and execute the procedure for point 3, would this still
>> trigger the corruption bug?
>>
>> Thanks,
>> Alessandro
>>
>> _______________________________________________
>> Gluster-users mailing list
>> Gluster-users at gluster.org
>> http://lists.gluster.org/mailman/listinfo/gluster-users
>>
>
>
> --
> Laura Bailey
> Senior Technical Writer
> Customer Content Services BNE
>
>
> _______________________________________________
> Gluster-users mailing list
> Gluster-users at gluster.org
> http://lists.gluster.org/mailman/listinfo/gluster-users
>
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Il 01/04/2017 04:22, Gambit15 ha scritto:
> As I understand it, only new files will be sharded, but simply
> renaming or moving them may be enough in that case.
>
> I'm interested in the arbiter/sharding bug you've mentioned. Could
you
> provide any more details or a link?
>
I think it is triggered only on rebalance.

Though I have still no idea if adding an arbiter afterwards needs
rebalance or not, and as this should only write file refernce (and no
data) on the arbiter, this should not touch anything on the data side. I
though wanted to be sure before doing this on a production environment.

The bug has been discussed in the mailing list. There are a couple of
patches that went into 3.8.10

https://review.gluster.org/#/c/16749/
https://review.gluster.org/#/c/16750/

though I'm not sure this solved the problem or not.

https://bugzilla.redhat.com/show_bug.cgi?id=1387878

If you look at the mailing list archive you can find more information on
this.

Currently I'm not using shardin, though as I'm using gluster to host VM
in case of some problems to one of the hosts healing would require lots
of CPU and time to recover the files.
Sharding should solve this, but I'd rather wait the time for it to heal,
then have to go through a restore from a backup cause there was data
corruption.

Any hint would really be appreciated.

Alessandro