Thanks Isaac, thats a great idea makes sense, it would depend on the network topology, but for MPLS networks there would be no additional traffic load.
On Tue, Mar 1, 2011 at 12:33 AM, Isaac Force <[email protected]> wrote: > >> Hi Niall, I think the key part is that with this topology your central > >> servers are going to need to support a sustained throughput of 20,000 > >> reads/second in order to distribute the updates to all 2,000 servers. > >> Granted, each read is repeated 2,000 times, so you'll mostly be reading > >> from page cache, but a cached read from CouchDB is not nearly as cheap > as > >> reading from e.g. Varnish. > > > > Thanks Adam, > > > > Thats a good point. I suppose we could scale this by adding more nodes in > > the data centre. > > An alternative would be to create peer-to-peer replication rings from > your edge nodes with a limited set of replication 'uplinks' to the > data center: draw nodes in an even ring, connect each node to its > adjacent peer to make a circle, connect each node to the node opposite > it in the ring, connect a set of nodes relative to the size of the > ring to the data center. > > If a set of nodes die, each node should still have an intra-ring path > to each remaining node, and as long as there's still one uplink > remaining replication from the data center will continue. You could > even connect the rings to one another and have the data center merely > be another node on one of the rings. > > This way configuration complexity and burden at the edge is traded for > egress replication burden from the data center. > > -Isaac >
