Feature Request: Temporary Archiving for Faster Sync of Small Files

[axone]

Summary:
Add an option to zip folders with many small files before syncing to greatly speed up transfers.

Problem:
I tried to back up a folder with about 2,500,000 small files. FreeFileSync processed them at around 20 files per second, making the sync take more than 1.5 days.
This isn't a bug — it's a natural limitation of file systems and copy overhead for small files — but it can be significantly improved.

I'm not alone in facing this issue — other users have also reported similar performance problems when syncing folders with millions of small files:
viewtopic.php?t=10205
viewtopic.php?t=8637
viewtopic.php?t=1120

What Worked for Me (Manual Solution):
To test an alternative, I manually:
1. Archived the entire folder into a single .zip file using WinRAR.
2. Copied the archive file to the destination manually.
3. Extracted it on the destination drive.

Result: The same folder copied in just a few hours instead of days — a 30× speed boost, just because I was copying one big file instead of millions of small ones.

Proposed Feature:
Add an optional "Archive Transfer Mode" to FreeFileSync that automates this workaround.

Suggested Behavior:
- Add a new toggle button, that if enabled:
1. FreeFileSync identifies folders with large numbers of small files.
2. It creates a temporary archive (for example, ZIP).
3. Transfers the archive instead of individual files.
4. Extracts the archive on the destination.
5. Deletes the archive after extraction (both on source and destination, if needed).

Key Notes:
- The feature should follow FreeFileSync’s existing sync rules (Mirror, Two-way, Update, etc.).
- The default archive format can be ZIP, or user-selectable.
- Compression can be optional, or use fast "store" mode for speed.
- Optionally allow users to define thresholds (for example, enable archive mode when folder contains more than 1,000 files).

Benefits:
- Greatly improved sync speed for folders with many small files.
- Reduces disk I/O load, especially on external HDDs.
- Offers major performance boost without changing the sync logic or structure.

Thank you for considering this feature. I believe it can make FreeFileSync even more powerful, especially for users handling large-scale backups.

[xCSxXenon]

Is there a possibility or has it ever been suggested that files are transferred tarballed? Would that be faster?

It has been suggested, and it will pretty much always be slower. The reason downloads are compressed is because thousands/millions of people download them, so the bandwidth decrease is worth the CPU time to compress/decompress it. This would also require FFS or some helper app to be installed on the receiving end of the data to perform the decompression, and one of the features of FFS is that it doesn't require installation on a remote machine.

Even if this was feasible, the amount of time it would take to compress and decompress is likely going to be larger than the time saved from transferring the smaller size