[Gluster-users] Automation of single server addition to replica

Lopez, Dan-Joe dan-joe.lopez at sap.com
Wed Nov 9 18:32:59 UTC 2016

Awesome, thanks Joe!!

To answer your question, it would be for improved availability.

Dan-Joe Lopez
PSD | DevOps CoE

Please consider the impact on the environment before printing this e-mail

From: Joe Julian [mailto:joe at julianfamily.org]
Sent: Wednesday, November 9, 2016 10:26 AM
To: Lopez, Dan-Joe <dan-joe.lopez at sap.com>; Gandalf Corvotempesta <gandalf.corvotempesta at gmail.com>
Cc: gluster-users at gluster.org
Subject: Re: [Gluster-users] Automation of single server addition to replica

On 11/09/2016 10:21 AM, Lopez, Dan-Joe wrote:
Thanks Joe and Gandalf!

I’ve look at the blog that you wrote Joe, but it seems to reference a more complicated scenario than I am working with.

We have a` replica n` volume, and I want to make it a` replica n+1` volume. Is that possible?

Dan-Joe Lopez

Sure, that's easy, add-brick $myvol replica $new_n $new_brick

but... why are you adding replica? Is it to improve redundancy and availability, or is it so you "have the same files on all our servers" (a common mistake)?

Another page that might be of use to you:

From: gluster-users-bounces at gluster.org<mailto:gluster-users-bounces at gluster.org> [mailto:gluster-users-bounces at gluster.org] On Behalf Of Gandalf Corvotempesta
Sent: Tuesday, November 8, 2016 10:54 PM
To: Joe Julian <joe at julianfamily.org><mailto:joe at julianfamily.org>
Cc: gluster-users at gluster.org<mailto:gluster-users at gluster.org>
Subject: Re: [Gluster-users] Automation of single server addition to replica

Il 09 nov 2016 1:23 AM, "Joe Julian" <joe at julianfamily.org<mailto:joe at julianfamily.org>> ha scritto:
> Replicas are defined in the order bricks are listed in the volume create command. So gluster volume create myvol replica 2 server1:/data/brick1 server2:/data/brick1 server3:/data/brick1 server4:/data/brick1 will replicate between server1 and server2 and replicate between server3 and server4.
> See also https://joejulian.name/blog/how-to-expand-glusterfs-replicated-clusters-by-one-server/

i really hope this could be automated in newer gluster versions
There is almost no sense to make a replica on the same server so gluster
should automatically move bricks to preserve data consistency when adding servers.

Ceph does this by moving objects around and you don't have to add servers in a multiple of replica

the rebalance command could be used to rebalance newly added bricks by preserving replicas in a proper state

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