How to protect against duplication of files when uploading to the server?

Question

Backend

What is the best way to save files on the server?
Previously, I wrote down an md5 hash for each file and, when uploading, I checked the hash of the new file with the one in the database, and if such a hash exists, the file was not uploaded, but the id of the previous uploaded file was given.
But, as I understand it, there is a high probability of a collision with md5. What is the best way to check files for duplicates then?

Answer 1

1) Store several different hashes, there are other algorithms besides md5
2) Before md5, also compare just the size
3) If EVERYTHING matches - for a complete exception - compare byte by byte

Answer 2

You can simply replace the hashing algorithm with BLAKE2b.