Assistance with files being damaged

[sosojni]

I am using Greyhole to backup my images folder. My problem is that i keep finding damaged images in my folders. I have them on 3 separate disks all of which are connected to mini pc via USB. Two disks are SSD disks and one is old HDD disk.
I see Greyhole has "calculate_md5 = yes" in it's greyhole.conf

Is that enough of protection or do i have to do something else to be sure files are not damaged while in transfer to those drives?

For example, i just found file (image) that was on 3 disks and all 3 copies are identically damaged. I have no idea how is that possible as they were synced from my mobile phone on which files are good. Landing zone is on local ssd disk inside mini pc and greyhole is moving them from there to external disks.

[gboudreau]

Hi,

With calculate_md5 = yes, the hash of new or changed files is calculated when new file copies are created, but that calculation uses the file that is read. What gets written should in theory always be the same, but Greyhole doesn't verify automatically.

To read the files (copieS) that were written, and ensure those have the same hash as the original, you'd need to run

greyhole --fsck --checksums ...

That would read ALL the file copies, and calculate the MD5 hash of those files, and compare it with the original MD5 that was saved in the MySQL DB when the file was last changed.
When it finished, it will report any mismatch found.
You can try it in a small folder that contains some files you think are broken, to see if it find those errors.
Check the greyhole log for a status update, and see when it completes.