If you have ever deploy your program on AWS, you may have experience to deploy your code on the EC2 VM. When you store all your data on the same VM, you may find your disc get full very quickly. It cost you a lot for your AWS fee. What most developer will do is to store data in another service called S3.
Are there any decentralized data system? The answer is yes. The most famous one is InterPlanetary File System (IPFS) Its an improvement of BitTorrent.