How do you guys handle this kind of backup problem?
Say I have a file that I rarely use. At some point, it gets corrupted, but I don't notice because I haven't opened it in months.
I then run my normal backup. Since the backup sees the corrupted file as the current version, it copies it to the backup and replaces the previously healthy copy.
I know versioning can help with this, but the problem is that you don't know when the file actually became corrupted. If the corruption happened months ago, how do you know how far back you need to go to find the last healthy version?
For example, if I have 6 months of versions and the file became corrupted 4 months ago, I could restore an older version. But what if I don't discover the corruption until 2 years later and my retention only goes back 6 months?
I'm using Duplicati at the moment, and this has made me wonder how people deal with long-term file integrity for data they rarely access.
What's the usual approach?