Does compare file content guarantee corruption free copies?

Discuss new features and functions
Delawar
Posts: 3
Joined: 21 Jul 2020

Post by Delawar

Hi. I do several copies of my backups for redundancy so I need them to be all exact copies. Since I have thousands of important files I'm a bit paranoid about any file getting corrupted. I just discovered FreeFileSync and I would like to know if the binary compare file content (and the verifycopiedfiles function that can be turned on) guarantees 100% that copied files are not corrupted in ANY way (as long as the original ones were ok obviously). If this function does not provide 100% peace of mind I would like to know why, and what I can do to achieve this or at least to get as close as possible (maybe using same methods big companies or the military do?). Thanks!
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Plerry
Posts: 1027
Joined: 22 Aug 2012

Post by Plerry

See the description relating to the VerifyCopiedFiles flag here, and the link provided there.
Only a guaranteed flush of all caches involved (e.g.by a reboot of all systems in the chain) can assure that data is read from disk. This beyond control of FreeFileSync.
Delawar
Posts: 3
Joined: 21 Jul 2020

Post by Delawar

Thanks for the reply. Then can you tell me how can I flush all caches involved? Is it as simple as rebooting my computer and re mounting my external drives and then performing a compare file content? or is it something more complex? (sorry my knowledge is limited in this area).
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Plerry
Posts: 1027
Joined: 22 Aug 2012

Post by Plerry

As long as all resources in the sync chain are fully under your control, there may be things you can do, like rebooting. However, if you run syncs to/from network- or even cloud-resources, those are often beyond your control and thus you may not always be able to flush and clear the cache in those resources.
The same may apply if your Windows is actually a hosted session running on a remote server, like is more and more common in medium scale businesses.
Delawar
Posts: 3
Joined: 21 Jul 2020

Post by Delawar

Thanks for the reply!. I just make copies in external drives I attach to my computer, no clouds involved. I'm not using Windows I use MacOS :)