[Gluster-users] geo-replicated Master Master cluster

Robert Hajime Lanning lanning at lanning.cc
Sun Nov 25 18:50:21 UTC 2012

On 11/25/12 08:59, Zohair Raza wrote:
> If it could be LAN then, normal replication can this requirement.
> Problem at both side is bandwidth, I need fast read/write access to
> local users and data would later get synchronized with other server.

Unfortunately, Gluster is not going to be a solution for you.

It's design goals have local replicas and an off-site, eventually 
consistent, one-way replica as a backup.

The geo-replication is basically a one-way rsync with smart file queuing.

> The all I understand about geo replication is, slave needs to be a third
> machine and if this is the case then I might need 4 machines?
> I have only two machines and I want something like master-master
> concept, I tried that but can not succeed.

Multi-master is Hard(tm) with the same issues as healing a split-brain 

How do you merge updates to a file from different sources, without full 
understanding of the file format.

Multi-master at the filesystem level usually means synchronous locks and 
writes, between all masters.

What you can do with Gluster is create a replicated volume that spans 
the sites.  Read requests should be satisfied from the local replica 
brick, while writes will be synchronous to both sites.  With quorum set 
correctly, if the link between sites goes down, then only the primary 
site will have access to the volume.

Mr. Flibble
King of the Potato People

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