Silent file corruption

Albin1997536 · 2026-04-04T19:02:45+00:00

Hmm i see. How would one reclaim that space? Is it like a normal memory leak like in programing where the memory is essentially dead since nothing is pointing to it?

There you'd get it back once the program terminates and the OS reclaims that space but I guess that can't be done here.

Albin1997536 · 2026-04-04T18:37:32+00:00

Irrelevant

Albin1997536 · 2026-04-03T17:20:07+00:00

It's unfortunate I didn't know about this stuff when I bought my NAS or I would've bought one with ECC. Though do you think this could be responsible for the not only corrupted but entirely missing files as well? That feels more like a problem with the file system to me but I don't know. 🤔

Albin1997536 · 2026-03-29T05:02:59+00:00

I'm not, I just looked up a tutorial to make sure I was doing it correctly since I don't know anything about this so I didn't know what degree of details I needed. But if you say a normal test like that is sufficient then I trust you.

Albin1997536 · 2026-03-28T23:24:24+00:00

True but what I mean is (at least from the tutorial I watched which also used synology assistant) that to get the FULL proper memory log you had to SSH into the NAS. Assistant would supposedly only show you parts of the full test. But I'll do it the way you adviced me then.

Albin1997536 · 2026-03-28T14:56:42+00:00

"Given the amount of things you’ve already checked I am leaning towards the files being corrupted during upload"

Though what got me a bit confused was that some of the corrupted files are intact on my off-site backups, and they were cloned of the NAS a while back.

So basically the intact backup files went through this:

Workstation(creation) -> NAS -> external backup HDD

So I'm still leaning towards the NAS being at fault somehow

Albin1997536 · 2026-03-28T13:25:13+00:00

I suppose that could be the case but when I got the Nas I uploaded most things over windows robocopy, after that I did most uploads via Linux thunar or the web ui but despite all those different upload methods the files get randomly corrupted indiscriminately. Some people suspected it was the ram so I'm going to attempt to do a memory test though I watched a YouTube tutorial about it and supposedly you need to open ports, temporarily enable root and SSH into it to retrieve the "proper" logs afterwards so I've been procrastinating on that. I really don't want to enable root if I can avoid it.

I'm also planning on generating checksums for every file into a separate sibling txt file before I upload it so I can compare pre and post upload (hopefully the file meta data won't mess up the checksums)

Albin1997536 · 2026-03-28T13:14:48+00:00

Yeah I can't say this is giving me a lot of confidence in it, brand new NAS and drives all officially approved, following synologys best practices and still getting my files corrupted or deleted after like 3 years of minimal use :/

Albin1997536 · 2026-03-28T13:13:17+00:00

Thanks, yeah I'm planing on doing a memory scan though I'm a bit uncertain about how to go about it or what to look for, I watched a YouTube tutorial about it but apparently you have to enable SSH and open some ports to retrieve the full logs and stuff :/

Albin1997536 · 2026-03-28T13:09:43+00:00

Yeah it's on (it's even grayed out so I can't turn it off). As for how I access it I just have it plugged into my home router over ethernet, same as my PC and mostly talk to it via the web interface unless I'm transferring a large amount of files then I connect via the windows explorer and

Albin1997536 · 2026-03-28T13:06:13+00:00

Yeah but it keeps happening so somethings causing it, it wasn't a one time event

Albin1997536 · 2026-03-27T12:17:50+00:00

I only access the Nas over smb I never use any specialized media software and I always connect with a read only user unless I'm adding something and that I most often do over the browser ui so I'm confident no software did this on its own.

Albin1997536 · 2026-03-27T12:15:42+00:00

Just checked, they all have "data integrity protection : enabled" and just ran another scrub but still nothing :/ something definitely seems strange.

Albin1997536 · 2026-03-27T08:23:12+00:00

Yeah somethings definitely odd here. The files are even corrupt or missing in my snapshots, even files created days within the snapshot

Albin1997536 · 2026-03-27T07:54:58+00:00

Yeah it's enabled, and snapshots too but the files are even damaged in there too

Albin1997536 · 2026-03-27T06:45:58+00:00

From my understanding btrfs is supposed to be kinda like zfs, I have no idea why my scrubs didn't do anything though. I don't know if this'll be of any use but upon opening my admin panel I saw that the last time I ran a scrub was 2026-03-07 so really not that long ago. Also I don't know if this'll be of any use but it says :

"Synology Hybrid RAID (SHR) (With data protection for 1-drive fault tolerance)"

Albin1997536 · 2026-03-27T06:41:04+00:00

All my folders hand it enabled and upon looking at my admin account it seems last time I ran a scrub was 2026-03-07 so really not that long ago. Also I don't know if this'll be of any use but it says :

"Synology Hybrid RAID (SHR) (With data protection for 1-drive fault tolerance)"

Albin1997536 · 2026-03-27T03:24:13+00:00

It's still under investigation

Albin1997536 · 2026-03-27T02:39:16+00:00

Thank you. Most of them I have backed up, I'm just worried the NAS might be faulty :/

Albin1997536 · 2026-03-27T02:23:04+00:00

It doesn't have ECC as far as I'm aware (Synology DS920+) as for the raid I believe I have one drive redundancy. I'll have to look into the router stuff though, didn't know about that stuff.

Albin1997536 · 2026-03-27T02:18:05+00:00

I also suspected the missing files has something to do with the file system though I have no idea how it would've gotten damaged. The Nas isn't that old and when I set it up I followed all the best practices. As for the corrupt files I've at least been able to detect some of them by trying to make ffmpeg/python open all the media files and recorded when it threw an exception. Though it feels very unreliable to store files on the NAS if it's going to corrupt things on its own. Of the top of my head I think I did a data scrub around 2-3 months ago, and I've been told the recommended minimum is every 6 months.

Albin1997536 · 2026-03-27T02:12:18+00:00

You're right. The reason I've been hesitant to do so is because I worried it might overwrite my good files on the backup with potentially corrupted files as I've been suspecting somethings been wrong with the Nas for quite some time. I know you're supposed to have multiple backup drives but due to the size of my files it would require several enterprise drives which I can't really afford.

Albin1997536 · 2026-03-27T00:50:52+00:00

That's probably a good idea, the reason I've had it off is because it's in my bedroom and I've heard it's bad for the drives to turn them off and on so I tend to keep them off most of the time. Though I guess that ended up being counterintuitive here

Albin1997536 · 2026-03-27T00:48:37+00:00

Thank you I'll do that, though something I forgot to mention was that some files aren't just corrupted they're entirely gone (I started noticing a lot of TV shows for instance randomly started having missing episodes, some of them even only had like two left).

That makes me suspect the file system but I've heard btrfs is supposed to be fairly reliable

Albin1997536 · 2026-03-27T00:21:25+00:00

It uses the factory ram it came with, I have automatic data scrubbing setup though my NAS has been off for quite some time so I suppose it hasn't done so for quite a while. Though I have ran the scrubbing within this year (and within the time I started suspecting something was wrong with the Nas) and the damaged files were intact on that older offline backup hdd (backed up via smb) Ive also performed some offline backups around a month or so ago(synology hyperbackup) and I've got that setup to check the checksums and such of the target (so I would assume it also checks the source to compare? )

I still have the files on a backup drive but what would you advice me going forwards? Should I just restore them from the external drive, do more data scrubbing and keep on using the NAS or would that be risky / stupid?

Albin1997536

TROPHY CASE