Gluster users - Mar 2017 - [Gluster-devel] Proposal to deprecate replace-brick for "distribute only" volumes

Makes sense.

On Thu, 16 Mar 2017 at 06:51, Raghavendra Talur <rtalur at redhat.com>
wrote:
> Hi,
>
> In the last few releases, we have changed replace-brick command such
> that it can be called only with "commit force" option. When
invoked,
> this is what happens to the volume:
>
> a. distribute only volume: the given brick is replaced with a empty
> brick with 100% probability of data loss.
> b. distribute-replicate: the given brick is replaced with a empty
> brick and self heal is triggered. If admin is wise enough to monitor
> self heal status before another replace-brick command, data is safe.
> c. distribute-disperse: same as above in distribute-replicate
>
> My proposal is to fully deprecate replace-brick command for
> "distribute only" volumes. It should print out a error "The
right way
> to replace brick for distribute only volume is to add brick, wait for
> rebalance to complete and remove brick" and return a "-1".
>
> Thoughts?
>
> Thanks,
> Raghavendra Talur
> _______________________________________________
> Gluster-users mailing list
> Gluster-users at gluster.org
> http://lists.gluster.org/mailman/listinfo/gluster-users
>
-- 
--Atin
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----- Original Message -----

From: "Atin Mukherjee" <atin.mukherjee83 at gmail.com> 
To: "Raghavendra Talur" <rtalur at redhat.com>, gluster-devel at
gluster.org, gluster-users at gluster.org
Sent: Thursday, March 16, 2017 4:22:41 PM 
Subject: Re: [Gluster-devel] [Gluster-users] Proposal to deprecate replace-brick
for "distribute only" volumes

Makes sense. 

On Thu, 16 Mar 2017 at 06:51, Raghavendra Talur < rtalur at redhat.com >
wrote:


Hi, 

In the last few releases, we have changed replace-brick command such 
that it can be called only with "commit force" option. When invoked, 
this is what happens to the volume: 

a. distribute only volume: the given brick is replaced with a empty 
brick with 100% probability of data loss. 
b. distribute-replicate: the given brick is replaced with a empty 
brick and self heal is triggered. If admin is wise enough to monitor 
self heal status before another replace-brick command, data is safe. 
c. distribute-disperse: same as above in distribute-replicate 

My proposal is to fully deprecate replace-brick command for 
"distribute only" volumes. It should print out a error "The right
way
to replace brick for distribute only volume is to add brick, wait for 
rebalance to complete and remove brick" and return a "-1". 




It makes sense. 
I just don't see any use of add-brick before remove-brick except the fact
that it will
help to keep the overall storage capacity of volume intact . 
What is the guarantee that the files on the brick which we want to replace 
would migrate to added brick? 

If a brick, which we want to replace, is healthy and we just want to replace it
then perhaps we should provide
a command to copy those files to new brick and then remove the old brick. 



<blockquote>
Thoughts? 

Thanks, 
Raghavendra Talur 
_______________________________________________ 
Gluster-users mailing list 
Gluster-users at gluster.org 
http://lists.gluster.org/mailman/listinfo/gluster-users 

</blockquote>

-- 
--Atin 

_______________________________________________ 
Gluster-devel mailing list 
Gluster-devel at gluster.org 
http://lists.gluster.org/mailman/listinfo/gluster-devel 

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