what is a solid workflow for long video recording sessions?

I'm trying to find an easy way to record my students presentations (with their knowledge), or my own lectures, on my phone. I already own a tripod for the phone, but my concern is what happens when it runs out of storage space. Since I can't put an SD card in my phone, is there any way to automatically upload video to the cloud (YouTube, Dropbox, etc) as it's recording? Or would I need to stop class and upload each individually after recording, then delete the video to guarantee room for others?

As an example case use, I'd have up to 20 students giving 6 minute presentations (2 hours of video), more or less back to back with maybe a minute of prep time between. I'm trying to find a workflow that would help me end up with a series of medium quality, private videos on YouTube. My phone can't hold that much video at one time, and I cannot risk a recording being cut short because I ran out of space.