Imagine a situation where you reach a limit of your current deployment—the number of shards is just not enough. For example, the indexing throughput is lower and lower, because the disks are not able to keep up. Of course, one of the possible solutions is to spread the index across more shards; however, you already have a collection and you want to keep the data and reindexing is not an option, because you don't have the original data. Solr can help you with such situations by allowing splitting shards of already created collections. This recipe will show you how to do it.