Yeah. Same as upgrading a PS3. One big enough to backup the current drive... one for the actual upgrade and then recover from the backup.
On PS3 I had to download firmware ... same has to be done with PS4... there are instructions on one of sony's websites...
One thing to note, as it seems to be a common mistake, make sure you're downloading the full PS4 firmware and not just the update. It will be the link under the "Download Now" button on the page the guide links to.