FreeFileSync Forum

Personally, I feel the default behavior should be FileTimeTolerance = 0 with no round down.

Although FAT is widely used, I wonder how many people actually use FFS for USB drives formatted in FAT rather than simple copy-paste. I personally only use FFS on my PC or external SSD and turn on version ...

"FileTimeTolerance" is a remnant from the beginning of the software when I thought having it configurable was a good idea.

Meanwhile I think it doesn't make sense to have this options set to anything other than 2 seconds, as long as the FAT format is still in general use. Also, higher precision ...

I'll need to look into this more, but honestly I'm scratching my head about why FreeFileSync needs to round down at all. Isn't that what FileTimeTolerance is for?

Hi
I noticed that even when I set FileTimeTolerance to 0, FreeFileSync still treats files with timestamp differences between 2ms to 77ms as identical.

After setting FileTimeTolerance to 0, I did notice more files being detected as different compared to the default setting. But such small timestamp ...

... Language Code="en_US"/>
<FailSafeFileCopy Enabled="false"/>
<CopyLockedFiles Enabled="false"/>
<CopyFilePermissions Enabled="false"/>
<FileTimeTolerance Seconds="2"/>
<RunWithBackgroundPriority Enabled="false"/>
<LockDirectoriesDuringSync Enabled="true"/>
<VerifyCopiedFiles Enabled="false ...

... FailSafeFileCopy Enabled="true"/>
<CopyLockedFiles Enabled="false"/>
<CopyFilePermissions Enabled="false"/>
<FileTimeTolerance Seconds="2"/>
<RunWithBackgroundPriority Enabled="false"/>
<LockDirectoriesDuringSync Enabled="false"/>
<VerifyCopiedFiles Enabled="false ...

... different time-stamp and thus cause a sync action.
6) Only if this results in less than 2 seconds (default) increase the the time stamp.
See FileTimeTolerance .
Or if the time-stamp difference matches exactly the "Ignore Time Shift" setting.

At least, you now seem to have eliminated the (partial ...

Your problem may be self-inflicted.
> I have set FileTimeTolerance to 0 ...

I tend to agree with Plerry here. The reason you're seeing a 1 second file time difference is (most likely) because the underlying file system is lacking precision.

https://freefilesync.org/forum/viewtopic.php?t=1183 ...

Further to my last remark just above:
As per the earlier description by Zenju (the author of FFS), your "Cannot determine sync-direction: No change since last synchronization" conflict is apparently considered to be of the 2nd category.

Your problem may be self-inflicted.
> I have set FileTimeTolerance to 0 ...
The simplest way to "fix" your problem is to change it back to the default setting of 2 seconds, as apparently even required for FAT/FAT32 file systems .

The "Cannot determine sync-direction: No change since last ...

According to my settings, the direction of the sync should always be from left to right.

I have set FileTimeTolerance to 0 and recently I discovered a strange behavior.

I use the "Mirror" variant with a database file. I have two files with 1 second difference in their modification date, but otherwise identical. When I try to sync, a message appears about these two files, saying "Cannot ...

Increasing the FileTimeTolerance may then possibly resolve the issue.

... As in maybe the Target is close to what you want, but not quite?

Might there be a "time difference" between the Mac systems, as in time is treated "differently", so where Mac sees them as "equal", there is an actual difference that FFS is picking up on (similar to FileTimeTolerance on Windows)?

That's what the "compare by file size" comparison variant is for.

... an ethernet link to another exFat drive running under Raspbian Linux.

FreeFileSync insists on re-copying all that data for some reason (14TB at 100 Mbps)

It appears to be a timestamp issue and I just thought setting <FileTimeTolerance Seconds> to 24 hours might eliminate any timestamp issue(s)

This setting should probably be removed. There exists no file system to my knowledge that creates offsets larger than two seconds. In theory this setting could be useful if you never use FAT* and be set to 0.

Does <File Time Tolerance Seconds> have a maximum size?

i.e. Can I set <FileTimeTolerance Seconds="86400"/> for 24 hours?

https://freefilesync.org/manual.php?topic=expert-settings
What if you change the "FileTimeTolerance"?

... DatabaseCache\Account\564236909.json
C:\Nycta\Servers\PoT\Server3\PathOfTitans\Saved\DatabaseCache\Account\564236909.json

Did you change FileTimeTolerance in GlobalSettings.xml?


Those files have been modified again since then, so unfortunately that I can't share the original time anymore. I ...

... times of these two files when "No change since last synchronization"?

C:\Nycta\Servers\PoT\Server2\PathOfTitans\Saved\DatabaseCache\Account\564236909.json
C:\Nycta\Servers\PoT\Server3\PathOfTitans\Saved\DatabaseCache\Account\564236909.json

Did you change FileTimeTolerance in GlobalSettings.xml?

... lock files. I am obviously not as geeky as I'd like to be or are you all are. This is what I've done . . . . of course it can be undone.

<FileTimeTolerance Seconds="2"/>
<RunWithBackgroundPriority Enabled="true"/>
<LockDirectoriesDuringSync Enabled="false"/>
<VerifyCopiedFiles Enabled="false"/>

...it's a FAT "feature"...

https://freefilesync.org/manual.php?topic=expert-settings
FileTimeTolerance:
By default file modification times are allowed to have a 2 second difference while still being considered equal. This is required by FAT/FAT32 file systems which store file times only with a 2 ...

... a couple of lines of code with comments:

//max. allowed file time deviation; < 0 means unlimited tolerance; default 2s: FAT vs NTFS
int fileTimeTolerance = zen::FAT_FILE_TIME_PRECISION_SEC;
...
const int FAT_FILE_TIME_PRECISION_SEC = 2; //https://devblogs.microsoft.com/oldnewthing/?p=83


The ...

... specified tolerance . Mind the Note in the purple text box in the Manual page on DTS issues .
This means your timestamp difference needs to be exactly the DTS setting.
If you have other timestamp related issues, you may try changing the FileTimeTolerance, which is a setting in the Expert Settings .

... I misinterpreted your last screenshot assuming that the two files had the same modification time in seconds (with a sub-second deviance). But the screenshot only shows minute resolution, so in reality the difference was probably 1 or 2 seconds, so with FileTimeTolerance = 0 FFS could detect this case.

... network shares (who knows what's used internally) and also smart phones.


In addition, would suggest that the Expert Settings page section FileTimeTolerance be edited/updated with notes on the above questions/issues.

In general the above should mostly be a non-issue: For this situation to occur ...

... out of XML document?

(2) Would there be any issue/problem with disabling (maybe setting to zero) this setting for people not using FAT/FAT32 file systems.

In addition, would suggest that the Expert Settings page section FileTimeTolerance be edited/updated with notes on the above questions/issues.

... but with a default tolerance of 2 s, it's not.

I noticed that there is a 3s discrepancy in the time of the NAS compared to the PC time, even though both use Internet time syncing (the PC is correct, the NAS is late). Could this be the cause?

I'll set the FileTimeTolerance to 4s to see if it helps.

I want to ignore Time Shifts less than 2 seconds when syncing.Bob4K

FFS already does this by default, see FileTimeTolerance.