[Gluster-users] Split-brain scenario

Rob S rtshilston at gmail.com
Fri Aug 15 19:29:36 UTC 2008

I apologise for taking this out of the original thread, but I didn't
feel my questions were really relevant to the original "Add/remove new
server volumes" subject

> > 2. Second, when using "files replicating strategy" (scheduler), is it
> >possible to remove a server node  without stopping the hole cluster
> >(ex. hardware maintaining reasons, add more disk/ram to the node ...)?

> if you have multiple servers AFR'ed, if one server is down, the rest
> will continue after the timeout period.  when that servers back on
> line it will coninue AFRing to it.
> Remember, AFR does healing when files are accessed, so the server
> that's offline may be out of sync until any updated files are accessed again.

Does this mean that the temporarily offline server A will be unaware
of changes to files made on server B until they are accessed on server
A, or on server B?

How does this extend to files that are created on B when A is offline
- at what point would A become aware of them?  On a "ls", or only when
an explicit attempt is made to open a file that's known to exist (even
though it doesn't yet exist)?

Finally, what sort of conflict resolution is in Gluster AFR?  If,
rather than A going offline, the communication between A and B is
unavailable, and different changes are made to the same file on A and
B, what happens?  I realise this is a highly undesirable situation,
but it'd be helpful to understand how Gluster / AFR deals with it.

I hope everyone has a great weekend,


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