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@xxxxxxxxxxxxxxxx]
Sent: Wednesday, November 9, 2016 10:26 AM
To: Lopez, Dan-Joe <dan-joe.lopez@xxxxxxx>; Gandalf Corvotempesta <gandalf.corvotempesta@xxxxxxxxx>
Cc: gluster-users@xxxxxxxxxxx
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:
https://joejulian.name/blog/glusterfs-replication-dos-and-donts/
From:
gluster-users-bounces@xxxxxxxxxxx [mailto:gluster-users-bounces@xxxxxxxxxxx]
On Behalf Of Gandalf Corvotempesta
Sent: Tuesday, November 8, 2016 10:54 PM
To: Joe Julian <joe@xxxxxxxxxxxxxxxx>
Cc: gluster-users@xxxxxxxxxxx
Subject: Re: [Gluster-users] Automation of single server addition to replica
Il 09 nov 2016 1:23 AM, "Joe Julian" <joe@xxxxxxxxxxxxxxxx> 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
