1. Disable Journaling: This is mostly recommended for development purposes. Journaling in MongoDB can consume a lot of memory as it maintains a record of changes to the database to recover it in case of a crash.
1. Use 32-bit Version: 32-bit versions of MongoDB have a limitation of 2GB data. But, it might help reduce memory consumption.
1. Use Lower Storage Engine: MongoDB supports both MMAPv1 and WiredTiger storage engines. WiredTiger generally consumes more RAM, so using MMAPv1 may help reduce memory usage.
1. Use Mongodump and Mongorestore: You can use the mongodump command to create a binary export of the contents of a database, and then use the mongorestore command to import data from the binary export created by mongodump.
1. Limit Indexes: Indexes can consume a considerable amount of memory. So, only index those fields which are required in a query.
1. Use Mongooplog: The oplog (operations log) is a special capped collection that keeps a rolling record of all operations that modify the data stored in your databases. But this also consumes memory. Hence, consider using a program like mongooplog, which can help in reducing memory usage.
1. Adjust WiredTiger Cache Size: If you’re using the WiredTiger storage engine (default in MongoDB 3.2 and up), you can adjust the WiredTiger internal cache size to use less memory.
1. Server Memory: Last but not least, increasing the server memory will also help in handling a larger set of data.
Remember, several of these options can affect MongoDB functionality or performance. It would be good to evaluate the impact of each method in a development environment before applying in production.
