How to approach the creation of an office file server with cloud backup?

Question

Backup

To store a large number of media files (raw video materials, editing, sound, etc.), we want to create a file server in the office, but with a mandatory backup system to the cloud.
Goals:
1. ensure maximum access speed (uploading new files, downloading existing ones);
2. provide reliable protection against damage / loss of data (if the server is stolen, damaged, turned off - the data will remain in the cloud);
3. from the moment of uploading files to the office server until the moment of backup to the cloud, protect data from damage.
Our volumes: 100-500 TB of media files. We thought to do it simply in Amazon S3 / Google Cloud Storage, but the download / download speed is not the best in office realities, it slows down the workflow a lot. Therefore, a local server is needed.
Suggest a solution to the problem.

Answer 1

You can try owncloud . It's like dropbox, only on its own server.
As for reliability, it is better to hire specialists, because there are a lot of nuances.
Well, it’s better to choose a data center for backups closer.

Answer 2

Well, if we consider the most inexpensive solution for 100-500Tb
2-10pcs. such here NAS .
And according to the mind - this is a server room, and rack-mount drives.