We have already seen the sharding, collection and replicas. In this section we will look at some of the important aspects of sharding, and how it plays a role in scalability and high availability. The strategy for creating new shards is highly dependent upon the hardware and the shard size. Let's say, you have two machines M1 & M2, of, the same configuration, each with one shard. Shard A is loaded with 1 million index documents, and shard B is loaded with 100 documents. When a query is fired, the query response to any Solr queries is determined by the query response of slowest node (in this case shard A). Hence having a shard with near to equal shard sizes can perform better in this case.