Smart Copy and Checkpoint Resume
Reflection for Secure IT UNIX clients and servers support features that help minimize the amount of time spent repeating unnecessary transfer of data.
Identical Files (Smart File Copy)
If a client user initiates a transfer and an identically named file already exists on the server, the server computes a hash of the server copy of the file and sends this value to the client. The client computes a hash of the client copy of the file and compares that to the value from the server. If the two hashes are identical, this indicates that the files are identical, and no data transfer occurs. The timestamp of the destination file is updated unless you transfer using the scp -p option.
Smart file copy is enabled by default. To disable from the client, set SmartFileCopy to no. To disable it from the server, set SmartFileTransfer to no. When smart file copy is disabled, existing files are always overwritten.
Automatic Resume of Interrupted File Transfer (Checkpoint Resume)
Reflection for Secure IT client and servers can resume an interrupted file transfer at the point at which the transfer was interrupted. For example, if a connection is dropped during a file upload, the client user can restart the transfer. The Reflection for Secure IT client determines the size of the file on the server, and requests a hash of that file from the server. The client computes the hash of the local file up to the length that the server already has. If the hashes are the same, the transfer resumes at that point in the file.
Note: Computing a hash to compare files does not produce useful data for ASCII transfers between systems with different line endings, so the hash comparison is skipped in this case and the complete file is always transferred.
Checkpoint resume is enabled by default. To disable from the client, set CheckpointResume to no. To disable it from the server, set SmartFileTransfer to no. When checkpoint resume is disabled, file transfer always starts over after an interruption.
Note: If you transfer files in a high latency network, the time required to send the hash values across the network can cause delays that exceed the benefit of using these features. In this case, you may be able to improve performance by disabling the smart copy and checkpoint resume features.