Timeout when calculating the remote checksum
The remote checksum calculation via SSH (as the sync criterion) seem to not work well with huge files – the files that take, say 20 minutes for their checksum to be calculated.
In WinSCP 6.3.6, I get "Host is not communicating for more than 15 seconds" warning shortly after the remote file checksum calculation is started (in ~15 seconds). Next, WinSCP waits for the "Automatic reconnect" timeout (if it's enabled in Preferences -> Transfer -> Endurance) and abandons the connection (BTW, the
As a workaround, it is possible to simply increase the "timeout" in the server connection settings (e.g. to 5000sec) for the Synchronization to work. But this is still just a workaround.
Technically speaking,
In WinSCP 6.3.6, I get "Host is not communicating for more than 15 seconds" warning shortly after the remote file checksum calculation is started (in ~15 seconds). Next, WinSCP waits for the "Automatic reconnect" timeout (if it's enabled in Preferences -> Transfer -> Endurance) and abandons the connection (BTW, the
sha256sum process on the remote server continues to run).
As a workaround, it is possible to simply increase the "timeout" in the server connection settings (e.g. to 5000sec) for the Synchronization to work. But this is still just a workaround.
Technically speaking,
sha256sum does not seem to provide any "--progress" or something, thus I'm not sure if there's an easy way to monitor the real progress. Maybe, as a better workaround, it is possible to add something like "expected minimum sha256sum speed (MB/s)" setting in WinSCP and calculate the actual timeout based on the file size.
