Big Data Storage Requirement

[EasternGamer]

Hello there, I'm considering using this for an application that will be storing a ton of potential data. I've read that it is an in memory database, so effectively the state of the database must be entirely in memory? So if you have 300 GB of raw data, it must all be in memory? I wouldn't expect any single client to view all that data, but I would use part of that data to construct a view for a client to see, with the most recent data being most relevant.

If you would need to store the entire database state in memory, are there any potential simple mitigations to still keep the old data around while, say, keeping the most recent data still available for fast use?

Are there other potential database solutions that match what I've described? It still needs to really fast for the use-case because it didn't get 300GB of data from nowhere.