How to check files for correctness before backing up?

Question

Backup

How to check files for serviceability, operability, absence of damage before backup? There were cases when broken files went into the backup. This is sadness. Those. I want to see a list of "bad" files using some program.

Answer 1

I think a CRC integrity check will do . This is really resource-intensive, but a fairly reliable method.
This way you can create checksums from the very beginning, when you know the file is good, and then verify when creating a backup, it is also useful to verify and restore a backup.

Answer 2

According to item 2, I clarify the question: in the table category Showing rows 0 - 24 (1254 total, Query took 0.0002 seconds.) [id: 1... - 25...]. I counted about 1310 unique categories by direct account on the donor site. what could be the reason for the discrepancy? worth checking out. thank.