I've had family reports of movies disappearing from the server, things they know they've watched. I didn't believe them at first, but noticed in Tautulli that there was an entry for a watched movie that was missing from the disk.

I installed Dynamix File Integrity and have let it run once a month for the past several months. I've had a few files on disk show up as corrupted now. When I go to the files (not movies in the latest examples), the filename is changed to something with the same file extension, but with a tilde in the filename, like it's an old deleted Windows file.

I have Parity run once a month, and a few days before that I have Dynamix File Integrity run.

What can I do, or how can I find the root cause of this file corruption, and prevent it from happening?

Memtest is a good place to start. Also, does the parity check typically find errors or not?

Alright, I'll start with memtest.

Parity Check only found errors back in Feb, the first time since 2022, and it was because of a bad HSA board, which has now been replaced.

Well, I got the green PASS banner, so I assume my RAM is good.

Any other thoughts?

Note that memtest is only definitive if it finds erros, but post the diagnostics mostly to look at the hardware used.

hagrid-diagnostics-20260528-1128.zip

No obvious red flags; and if the latest parity checks haven't found any errors, it's unlikely that it would be a hardware issue.

Well crap. Just "bitrot" then, maybe?

That would be detected on a parity check

That would be a message of Errors found during Parity, right?

Will Parity correct an error found on disk, in the case of bitrot or something?

6 hours ago, duffbeer said:

Will Parity correct an error found on disk, in the case of bitrot or something?

No.

Parity and the array will just be out of sync, you would either have to rebuild the drive trusting parity is correct (cant verify)

OR

Sync parity to the current data.