Lightroom Workflow and Backup

Hi All,

I am working in Lightroom 7.1.2 and have a question about workflow.  I currently send all my photos to the cloud and back up to and SSD drive.  I have run out of space on my SSD drive and wanted to introduce a new drive, however when I plug it in, Lightroom starts moving the entire digital library to the new drive vs just the new material.  Is there a way to work with two drives?  Or is there a better way to deal with the storage issue?  

Thanks!