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Thanks Christian.
That reply covered everything I was seeking to know on this subject.


On Fri, Apr 4, 2014 at 3:11 PM, Christian Schwede <
christian.schwede at enovance.com> wrote:

> Hi,
>
> Am 04.04.14 11:14, schrieb Shyam Prasad N:
> > I have a question regarding the ring building process in a swift cluster.
> > Many sources online suggest building the rings using ring-builder and
> > scp the generated ring files to all the nodes in the cluster.
> > What I'm trying to understand is if the scp step is just to simplify
> > things, or is it absolutely necessary that the ring files on all the
> > nodes is exactly the same?
> > Can I instead individually build the rings on each node individually?
>
> no, the ring files must be the same on all nodes.
>
> Ring files in combination with the full object name define which storage
> nodes are responsible for the object.
>
> A very simplified example with four storage servers A, B, C, D and only
> two replicas:
>
> 1. The proxy server wants to store an object and based on its ring file
> decides that storage server "A" and "B" should store it.
>
> 2. The storage nodes "A" and "B" use different ringfiles; their
> replicators now assume that the object is misplaced and will replicate
> the object to nodes "C" and "D".
>
> 3. Now the proxy wants to get the object sometime later, and because of
> the different ring expects the object on server "A" and "B". But the
> object is no longer stored on these servers and the request will fail.
>
> Christian
>
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>



-- 
-Shyam
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