Tom, There is no hard and fast rule for the "best value." The optimal value for your situation will need to take into account the physical resources available both in your starting cluster as well as your planned end-state cluster. If you plan to use secondary indexing, the maximum ring_creation_size you should consider is 512. There will be a separate concurrent vnode_proxy process for each vnode, and a process for each backend for each vnode. Each backend will need open file handles and RAM for caching objects. The backend configuration section of the docs should help plan your backed settings http://docs.basho.com/riak/1.3.1/tutorials/choosing-a-backend/ Your planning must also include failure scenarios. If any of your nodes crash, the surviving nodes will each start more vnodes to cover the missing node(s). The 10 vnodes per node recommendation is to ensure that the vnodes from any single failed node can be divided among enough surviving nodes to not leave one node handling significantly more load than the other, but this also is not a hard and fast rule. At this time changing number of partitions in the ring does require a complete rebuild of the cluster, we do have dynamic ring sizing on the product roadmap, but there is no release date set for that feature.
Joe Caswell From: Tom Zeng <[email protected]> Date: Sunday, April 21, 2013 9:38 PM To: <[email protected]> Subject: the optimal value of the ring_creation_size Hi, I am wondering what's the best value for ring_creation_size, the default is 64. According to the docs 64 will work for a cluster of no more than 6 nodes (64 /10), and ring_creation_size of 128 will allow cluster of up to 12 mode. I am wondering what kind of overhead of is associated with a large ring_creation_size. Since changing the ring_creation_size will result in rebuilding the cluster(destuctive), would a larger value make more sense and allow scaling by adding more nodes? Thanks, Tom -- Tom Zeng Director of Engineering Intridea, Inc. | www.intridea.com <http://www.intridea.com> [email protected] (o) 888.968.4332 x519 (c) 240-643-8728 _______________________________________________ riak-users mailing list [email protected] http://lists.basho.com/mailman/listinfo/riak-users_lists.basho.com
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