Choose the volume required to store the data used by your DRP.
Please bear in mind that the volume does not only include the current size of your servers, but also the history of updates you will be planning.
You will be free to delete backup points, but you must make sure you keep what you need.
When you activate your DRP, you’ll have the freedom to choose which version (based on date and time) of the backup will be used to start your DRP.