I am trying to copy ~2TB of data, mostly photos images archive and my source code file. So few thousand of files with size up to 10MB. Sync between freebsd (0.14.5) on zfs and ubuntu (0.14.5) on ext4 over local 1Gb lan. My observation is when I start both computers the replication is running with speed 20MB/s for 45 min - 1h. After that time the speed slow down to few kB/s without visible bottleneck. So in consequences, after 1h I have ~70GB replicated but when I left computer for whole night (10h) I have just about 150GB in sync state. Do you have such observation as well? What can be a reason for this? Regards.
There is per file overhead, so as syncthing progresses towards more smaller files the rate will drop.
I did a test with 10 TB (synthetic data) and at least in this case the sync speed doesn’t seem to differ significantly as it goes along. It’s almost done now, started last night: