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

[Joe Julian]

On March 16, 2017 4:17:04 AM PDT, Ashish Pandey <aspandey at redhat.com> wrote:
>
>
>----- 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. 

We used to have a command that did just that. It was replace-brick.

>
>
>
><blockquote>
>Thoughts? 
>
>Thanks, 
>Raghavendra Talur 
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>Gluster-users at gluster.org 
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>
></blockquote>

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