FTP transfer file corruption

Posts: 6 · kelna 27 Oct 2021, 21:01

Lately I had severe issues with FTP syncing. I use FFS to sync three computers and an FTP server (each PC syncs with the FTP server). The protocol is "explicit TLS/SSL".

The setup worked quite well for some time, then this strange error occured: Some PRPROJ files (Premiere Pro project files) were corrupted. I was able to recreate and examine the phenomenon as it happened multiple times. What happens is that I have a good project file on my computer, run a sync, it gets transferred as a new file to the server but the new file on the server is corrupted. It's only 32 kB, exactly 32768 B, even though the original file is bigger, 40-50 kB. During the next syncing, the good file gets overwritten as it appears to be "older" because a file size change happened on the server. So now all the copies are corrupted.

Any ideas how this can happen and how to avoid it?

Posts: 4867 · xCSxXenon 28 Oct 2021, 14:53

That is pretty much always a server issue. Have you power cycled the server? What is the server?

Posts: 1202 · therube 28 Oct 2021, 15:19

(Totally different situation, but similar sounding, AutoCAD File Corruption after installing [Everything] 1.4.1.935.)

Posts: 6 · kelna 28 Oct 2021, 17:47

That is pretty much always a server issue. Have you power cycled the server? What is the server? xCSxXenon, 28 Oct 2021, 14:53

The server is a Synology DS220j NAS. I didn't try to restart it yet. It's in a datacenter so I'm hestitant, but I could give it a try during working hours.

Posts: 6 · kelna 28 Oct 2021, 17:49

(Totally different situation, but similar sounding, AutoCAD File Corruption after installing [Everything] 1.4.1.935.) therube, 28 Oct 2021, 15:19

Thanks for the tip! I read through the topic and don't find it similar, although I'm not familiar with that software. The solution there was to turn off some features that FFS doesn't have.

Posts: 6 · kelna 28 Oct 2021, 17:59

I forgot to point out an important detail! I can copy the files without problem with WinSCP. So the server is probably not the source of the error.
When I tried to recreate the issue this happened:
1. Sync with FFS -> corrupted 32 kB PRPROJ file gets copied to the server.
2. I delete the bad file from the server.
3. Retry syncing, same result
4. I delete the bad file again.
5. I copy the file from my computer to the server (same destination) via WinSCP and it works.

I should also point out that during the first occasion when this occured, I synced up to the server a PRPROJ file smaller than 32 kB and it didn't get corrupted. So this seems to be a problem only with >32 kB files.

Posts: 1202 · therube 28 Oct 2021, 19:15

this seems to be a problem only with >32 kB files

Is that >32 kB AND PRPROJ files?
(As in you can successfully backup other non-PRPROJ files >32 kB without corruption?)

FTP syncing

And if you use a method other then FTP, will that complete successfully?

The protocol is "explicit TLS/SSL".

If you set up "straight" FTP (not FTPS), will that complete successfully?

Posts: 6 · kelna 28 Oct 2021, 22:19

this seems to be a problem only with >32 kB files
Is that >32 kB AND PRPROJ files?
(As in you can successfully backup other non-PRPROJ files >32 kB without corruption?)

FTP syncing
And if you use a method other then FTP, will that complete successfully?

The protocol is "explicit TLS/SSL".
If you set up "straight" FTP (not FTPS), will that complete successfully? therube, 28 Oct 2021, 19:15

Yes, so far only PRPROJ files were affected and only two files.Those however were corrupted more than once, as I tried multiple times. I'll try the vanilla FTP and SFTP method tomorrow. I don't think I can use other methods but I'll think about it.

Posts: 7506 · Zenju 1 Nov 2021, 19:27

Is this bug dependent on the FFS version? Did you have a look of the contents of the 32 kB corrupt file? Might give a clue regarding what happened. Most likely the server is somehow fiddling with the file, since you mentioned the time stamp is newer than the source file's.

Posts: 6 · kelna 5 Nov 2021, 11:10

I haven't tried older versions yet. It's a good idea to look into the corrupted file, but I missed that opportunity unfortunately, as I already deleted the files. The issue haven't happened since, but I'm on the lookout.
I don't think the server is the issue. Maybe I didn't phrase it precisely: the timestamp of the corrupted file is not newer on the server, but the filesize changes and FFS sees the change compared to the last state, that's why it downloads the corrupted file and overwrites the good one.