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 < [email protected]> 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 > > _______________________________________________ > OpenStack-dev mailing list > [email protected] > http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev > -- -Shyam
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