A number of points: * The replication factor (N) * the total original data size = total data size stored in the cluster. For example, if N=3, then you have 300GB of data stored across the cluster. If you had 6 nodes, this would be about 50GB per node. * Riak can be optimized in your setup for GET speed, but in general it is optimized for fault-tolerance and availability. Even in the best of conditions, it will not perform as optimally as a web server reading static files off the local disk. * The replication factor will affect both reads and writes. If your cluster size is larger than your N, you should see increased throughput as you add nodes.
Sean Cribbs <[email protected]> Developer Advocate Basho Technologies, Inc. http://basho.com/ On Apr 12, 2010, at 1:19 PM, TuX RaceR wrote: > Hello Riak users! > > Let me first present on a simple example what I can see as an application > that 'scales': > If a have a web server (e.g apache) serving 100Gb of files and I get 4000 GET > per seconds, one way to scale the application is to copy (rsync) the 100Gb to > another web server and balance the load on the two nodes: that way, globally > my cluster of 2 nodes can serve 2 x 4000 GET per seconds. > I can say that my architecture scales as if I multiply by 2 the number of > nodes, then I can multiply by 2 the number of requests that the system can > handle (per second). > > With Riak, I am not sure to understand how the scaling works. Are we speaking > about a global 'key GET' rate (request per second) that scales with the > number of nodes added? > My web server example above also assumed that all the data (100Gb) could fit > into a single node. As I understand Riak could be used to serve data too > large to fit on one disk. So maybe the scaling is about the data itself: a > web client (browser) will not see a speed difference in the response from a > riak cluster serving K keys with N nodes and another riak cluster serving 2*K > keys on 2*N nodes. > > Also the number of replicas role in scaling is not clear to me: it seems to > me that having a lot of replicas speeds up reads but slows down writes. Is > there a simple scaling law for this? > > Thanks in advance, > > TuX > > _______________________________________________ > riak-users mailing list > [email protected] > http://lists.basho.com/mailman/listinfo/riak-users_lists.basho.com _______________________________________________ riak-users mailing list [email protected] http://lists.basho.com/mailman/listinfo/riak-users_lists.basho.com
