Bug? using accessed date instead of modified date

[databoxer]

I just copied a large group of old USB backup drives to a folder on my 24TB Synology NAS and then to a 14TB USB drive, formatted with NTFS. When I use FreeFileSync (v12.0 on Win64) to compare the NAS folder to the USB drive contents, it compares using the Accessed Date on the USB instead of the Modified Date, so everything miscompares. When I look at the individual files on the USB (either using Properties in Windows Explorer or DIR from the command line), the Modified Date is correct and matches that from the NAS. The Access Dates are from the last few days, while the Modified Dates are from 5-15 years ago. This is very frustrating, as I want to make sure the two set of files are identical.

FYI, this problem also happened with the latest version 11.xx of FFS. I just installed the new version to see if it would fix the problem, but no luck.

I'm very baffled -- I have been using FFS for years and have never seen this behavior before.

Any thoughts/ideas on what is going on? Thanks!

[therube]

Windows Explorer to the NAS & Windows Explorer to the USB show the same modified dates?
Might seconds be off between the two?

Tell us about your 14TB USB?

What OS/filesystem on the NAS?

Have you always had this issue or was everything OK with FFS < 11.x ?

[databoxer]

Yes, Windows Explorer shows the exact same modified date on the NAS and the USB. The dates show by FFS are off by 10+ years, not just a few seconds. For example, one file was modified in 2012 and last accessed yesterday -- the latter time/date is shown in FFS.

It's a WD Elements 14TB external USB drive. I have a couple of the 12TB versions of that drive family which I have used for a few years with the same NAS without any problems.

The NAS is a DS1520+ with five 8TB drives in RAID 5, for 24TB of usable space. It is running DSM 6.2.4. I've had it for a couple of years, with no problems until this case.

Both FFS v11 and v12 have the same issue, but only with this new USB drive. Very strange why it should pick the accessed date instead of the modified date

[databoxer]

Maybe I figured something out. For speed reasons, I had performed the file copy from the NAS to the USB drive via the DSM console, plugging the USB directly into the NAS. I just tried that again with a much smaller subset of the files (40GB instead of 10+ TB), and the same problem results. So maybe it's a bug in DSM handling of NTFS file dates? Not sure why Windows sees the correct modified date, but FFS doesn't, but the condition only seems to happen when DSM (not Windows) does the copy. It still could be an FFS issue, but I'll pursue with Synology support as well. I have attached a screenshot that shows the problem

[Zenju]

So maybe it's a bug in DSM handling of NTFS file dates? Not sure why Windows sees the correct modified date, but FFS doesn't, but the condition only seems to happen when DSM (not Windows) does the copy.

Interesting. I suspect the "DSM copy" did not explicitly set a modifcation time, in which case the copied files would default to "now". So the modification time shown in FreeFileSync is probably "correct".

But why is Windows Explorer showing a different value in the "Date" column? It's probably pulling the date from the jpg metadata, and not showing the actual file modification time.

[databoxer]

Ah, that could make sense, though (like you) I wonder then how Windows got the correct date. I would have to check if this only happens with JPG files. In any case, I have raised the issue with Synology support, so we'll see. What I also found very odd is that, if I pressed "compare" again in FFS, a *different* subset of files miscompared due to the date! The first time, for example, files 1-150 miscompared. Then files 41-150 miscompared on the second attempt. On the third try, files 81-150 miscompared, and then after that it stayed stable at 81-150. Something very weird is going on.

Thanks!

[therube]

If it is image related, then, Dates are not Date Taken, but are EXIF Date and Time (original/digitized).
(I've not read it, so wouldn't know if it might still apply, currently.)

On my end, my NAS is simply a storage device, containing bits & bytes, & anything that goes on to it is simply copied there. There is no (Synology) utility that "interprets" any of that data (like pulling out EXIF data).

[databoxer]

I just heard back from Synology that this date problem is a known issue with copying from NAS to USB within DSM. Next time I'll just copy with Windows, even though it will be slower (due to the 1Gbps ethernet limit).

Thanks for your help.