Under the storage key, the following table summarizes the more widely used options:
| Key | Sub key | Notes |
| dbPath | Directory where the actual database files reside. | |
| journal | enabled | Possible values: true | false. If set true, journaling is enabled. |
| journal | commitIntervalMs | This represents the interval between journal commits. Values can be from 1 to 500 milliseconds. The default is 100. |
| engine | The default is wiredTiger. You can also specify inMemory, which activates the in-memory storage engine. |
There are a number of other parameters as well; however, these are covered in other chapters in the book as appropriate.
