Hi,
for quite a while I have I Question about Bitflipping and syncing. Imagine I have got a folder of Audio files synced with syncthing over 4 different devices. What happens when some bits flip so that, the files can not be played or louses metadata. I think even this unwanted change would be synced, resulting to up to four times higher loss rates (best case), or a bit higher loss rate than the highest lossrate on all devices. How can this be resolved?
By using a raid or a error checking filesystem. Syncthing syncs files, it does not protect you from your files being deleted, corrupted or what not.
You could use versioning on all devices, but I doubt we’d pick up a bit flip as a change, as I suspect the size or metadata of the file wouldn’t change, so it would just be unplayable on one device.
Use a filesystem that protects against this, such as ZFS. Syncthing has no choice but to trust what the filesystem claims is the file contents.
Hard drives manufactured since 1980 store checksums in each sector and will return a read error (bad sector) if a bit has flipped. https://en.wikipedia.org/wiki/Error_detection_and_correction#Data_storage Note that this is a lower level than the filesystem. Newer drives can sometimes correct single bits but the chance of a mis-correction is statistically extremely remote. The only time I have had file corruption, it was a bad RAM bit in the computer that was corrupting files as they were written to the drive.