I think this has a big thing to do with, how much data you have on your server… If you have a gigabyte of data it would obviously take less than 20 gigabytes. I can’t really give a exact time, because there are multiple other variables… that would impact the amount of time it might take to do this.

I have a 30G droplet with 14G used, usually the snapshot will take about 11 minutes.
Two hours seems abnormal.