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3.3. Sharding indexes In some cases it can be useful to split (shard) the indexed data of a given entity into several Lucene indexes. Warning This solution is not recommended unless there is a pressing need. Searches will be slower as all shards have to be opened for a single search. Don't do it until you have a real use case! Possible use cases for sharding are: A single index is so huge that index update times are slowing the application down. A typical search will only hit a sub-set of the index, such as when data is naturally segmented by customer, region or application. By default sharding is not enabled unless the number of shards is configured.