How to avoid warning with file system cache in mongodb?
Any ideas how to avoid warning?


This warning was added for some older implementations of MongoDB's WiredTiger storage engine, but is longer relevant in MongoDB 3.6. The warning has been removed in MongoDB 4.0 and the removal has been backported for the upcoming MongoDB 3.6.6 server release. See SERVER-33706 for more background.

You can ignore this warning until you upgrade to a version of MongoDB newer than 3.6.5.


  Then getting the error Unrecognized option: storage.inMemory.engineConfig.inMemorySizeGB 


This configuration option is for the In-Memory Storage Engine which is included in MongoDB Enterprise, and not relevant to the filesystem cache warning. The option will not be recognized unless you are running MongoDB Enterprise server.