As lots of people prefer to backup data to multiple backup storage, this is not a perfect choice.
Lets say a video file stored in a server which connected to hundreds of other server in cluster. The backup mechanism automatically backup every day to backup storage.
But one day, bad sector happen (permanent disk damage) which affect that video file.
Backup mechanism just backup the video as usual. *nix server dont know if that video file is damaged because of disk damage. after 2 months, the older backup snapshot automatically deleted from backup storage. so, all copy of that video file is broken file.
When a visitor trying to play video of that video file, it will stuck in the middle. Imagine this happen in youtube. this is shame.
I believe backup mechanism like this is not effective and needs too much space.
So what is the best way to backup data from disk failure?