[Gluster-users] Avoid Split-brain and other stuff

[Joe Julian]

http://community.gluster.org/q/what-is-split-brain-in-glusterfs-and-how-can-i-cause-it/

On 11/16/2012 12:28 AM, Brian Candler wrote:
> On Fri, Nov 16, 2012 at 08:37:01AM +0100, Martin Emrich wrote:
>>> Any multi-master replication suffers from exactly the same split-brain
>>> scenarios as you described earlier.
>> That would be perfectly acceptable, as long as it would heal deterministically (last one wins, or renamed conflicting files)
> Not for me it wouldn't. "Last one wins" means "one set of updates thrown
> away", i.e.  definite data loss, which will be compounded when further
> updates take place.
>
> Automatic renaming means either that the file vanishes from its original
> name (so the application which looks for the file breaks anyway), or that
> one version has the original name and the other version is renamed - which
> can also result in irrepairable damage.
>
>>> In glusterfs, geo-replication is what you should use for WAN-separated sites.
>>> Replicated volumes are for LAN scenarios where partitioning (and hence split-
>>> brain) should not be expected to occur.
>> Hmm, then I wonder how a high-availability scenario would work, if it is not allowed for a node to go down in a replica-mode setup...
> Certainly a node can go down, come up again later, and while out-of-date it
> will resync.
>
> What you don't want is both nodes to be up, both reachable only by a subset
> of clients, and updates occurring on both.
>
> Regards,
>
> Brian.
> _______________________________________________
> Gluster-users mailing list
> Gluster-users at gluster.org
> http://supercolony.gluster.org/mailman/listinfo/gluster-users