As immediately as the cluster can detect the node is no longer serving requests[1]. There will likely be increased network and IO among the remaining nodes as they will be picking up the slack. That said, the data is not permanently reshuffled at that point - only such time as it is administratively removed. The degree to which you’d see a spike depends on the volume of objects, # of physical nodes, and # of partitions/vnodes.
[1] http://docs.basho.com/riak/latest/theory/concepts/Replication/#Processing-partition-requests On March 24, 2014 at 10:43:36, Jeff Peck ([email protected]) wrote: Does that happen immediately? I am basically trying to understand: When a physical node goes down (let's say it is temporarily restarted, or down for even a couple hours due to some sort of failure), will that cause an increase in disk and network bandwidth at the moment that it goes down as data is re-shuffled across the cluster? Thanks, Jeff On Mar 24, 2014, at 1:38 PM, Seth Thomas <[email protected]> wrote: Data is redistributed temporarily (indefinitely) until the primary node comes back online. So primary ownership of data would not be changed but your keys could be living on another physical node if any of the primary replicas were down. So to answer your question directly: Yes (in the narrowest definition) On March 24, 2014 at 10:34:22, Jeff Peck ([email protected]) wrote: Thank you. So, does that mean that no redistribution of data would occur unless the node is manually removed? - Jeff On Mar 24, 2014, at 1:31 PM, Seth Thomas <[email protected]> wrote: Jeff, When a node is no longer responding a process called hinted handoff[1] takes over and ensure that your N (replication) value is met by allowing other nodes to temporarily take responsibility for the vnodes of the downed node. This node can return to the cluster and will resume operations for the vnodes it’s primarily responsible for or you could remove the node[2] from the cluster which would redistribute the primary responsibly among the remaining nodes. I’d also give our docs on replication[3] a look for more information. Seth Thomas [1] http://docs.basho.com/riak/latest/theory/concepts/glossary/#Hinted-Handoff [2] http://docs.basho.com/riak/latest/ops/running/nodes/adding-removing/#Removing-a-Node-From-a-Cluster [3] http://docs.basho.com/riak/latest/theory/concepts/Replication/ On March 24, 2014 at 9:33:17, Jeff Peck ([email protected]) wrote: Is there a description of what happens internally when a node goes down? I am curious if any there would be any sort of reshuffling or redistribution of data in the remaining vnodes? Or would the node simply be unavailable until restarted? Thanks, Jeff _______________________________________________ riak-users mailing list [email protected] http://lists.basho.com/mailman/listinfo/riak-users_lists.basho.com
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