The mechanism of rclone sync

I have a question about the mechanism of the rclone sync. I have 1000 pdf files in my local computer and remote google drive. The total size of all files is 2.5G.When I make change one file in my local computer and run sync cmd, the rclone will make compare with all files in local computer and remote google drive? So the network flow will be 2.5G? So the sync cmd will be very slow?

If the remote supports hashes rclone will compare a checksum for each file.

Does the google drive support the Hashes?

Have a look at the Overview of cloud storage systems. It lists Google Drive as supporting MD5.


With the default flags, rclone will compare the size and modification time only to decided if a file needs uploading again. If you use the --checksum flag then it will compare the checksum of the file - google drive supports both.

So you should find that after the first sync, the network flow is only the new files. If there are no new file, the network flow will be very small.