SQL Server effectiveness of mirroring partial database

Our database stores 200 TB of data. We've setup clustering options of two VM nodes with one storage but due to limited resources, we cannot replicate the entire database for disaster recovery (only about 100 GB can be spared at most). So, I was wondering if it's possible to mirror partial portion of the database. 1. Distinguish active data, pull them into separate database (maybe at most 20 GB worth of active data) 2. Setup database mirroring for new database Questions: * If partial database is mirrored, should I be worried about performance issue? * Are there other known solutions to prepare for DR situations? It may be hard to provide best answer without knowing the detailed specs of servers, and configurations but I'd like to know how other servers are handled with limited resources. Thank you!