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Configuration The hints are configured at transport level: Following topology hints can be specified: machineId - this is probably the most useful, to disambiguate between multiple JVM instances on the same node, or even multiple virtual hosts on the same physical host. rackId - in larger clusters with nodes occupying more than a single rack, this setting would help prevent backups being stored on the same rack. siteId - to differentiate between nodes in different data centres replicating to each other.   All of the above are optional, and if not provided, the distribution algorithms provide no guarantees that backups will not be stored in instances on the same host/rack/site.