In a sharded MongoDB cluster, scale and data distribution are defined by your shard keys. Even when choosing the correct shards key, ongoing maintenance and review can still be required to maintain optimal performance.
This presentation will review shard key selection and how the distribution of chunks can create scenarios where you may need to manually move, split, or merge chunks in your sharded cluster. Scenarios requiring these actions can exist with both optimal and sub-optimal shard keys. Example use cases will provide tips on selection of shard key, detecting an issue, reasons why you may encounter these scenarios, and specific steps you can take to rectify the issue.