High Data Volume from remote size during one-way sync

[pnbqLEiMohaSxU129ykR]

We are using Donation Edition to mirror files from local storage in one office to a remote office location. The following options are selected:

Comparison - File Time and Size
Filter - Default
Synchronization - Mirror (Add left to right, update left to right whether newer, uncategorized, older and delete from right side) - detect moved files is not enabled, delete files: permanent.

When the sync jobs run, the network traffic is extraordinarily high in both directions, left to right (expected) and from right to left (unexpected). The only explanation we can conceive of for this is if the files are being read from the remote (right) side during the synchronization even though they have not changed. Is this possible and if not, what else could account for the sent data to be so high?

[pnbqLEiMohaSxU129ykR]

We are still facing this problem and will have to start looking for alternatives to continuing to support FreeFileSync through donation renewal if no solution can be provided.

[Zenju]

Traffic flowing both directions is expected in any network communication. Whether the amount of traffic from right to left is too high is hard to tell. I'd suggest comparing the numbers with copying with Windows Explorer and see if there is a difference. There probably isn't since FreeFileSync is using the standard Windows copy routine CopyFileEx for data transfer.

[pnbqLEiMohaSxU129ykR]

Thank you. The sync profiles are all set to Mirror from local to remote. In this situation, would the remote file be ready from the local side in order to do a compare? The VPN client that is running shows the amount of data transmitted and received and when a sync is running, the amount of data is nearly the same in both directions. This seems to indicate even though we are not doing checksums and it is set to use the file date/time for comparison, the entire remote file is being read by FreeFileSync, or do you have another idea of what could be causing this? We have tested that it is from FreeFileSync by stopping the sync and seeing the data transfer stop immediately through all tests. I have tried reading up on the functionality of CopyFileEx to see if there is something that covers this but I haven't been able to find anything unless it has to do with buffering of the file to memory, but it seems that the file size/date check would use metadata, not read the entire remote file to memory to determine if it is the same or needs to be updated.

[Zenju]

Perhaps you have VerifyCopiedFiles active, which would explain the equal amount of traffic in both directions.

[pnbqLEiMohaSxU129ykR]

I am the only person who has installed/configured FreeFileSync and know that I had not edited this file, but verified to ensure that no one else had done it without my being aware - this is set to False. Is there anything else I can examine for potential causes?

[Zenju]

I'd suggest using tools like Process Monitor and/or Wireshark to analyze the network traffic.