How to preserve index data

Sorry if this question is elementary: we need to preserve index data from time to time so we don't have to reload the whole index from scratch.

How do I do that exactly!? Which portion of the /data path do I need to preserve so I could just restore it back to a given point in time without ill effects?!

We just have one node right now, the path looks like this on RHEL:

Can I just tar up all of the contents below and restore them if needed?

Use the snapshot and restore functionality in Elasticsearch.