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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

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.

Automatic Resume of Interrupted File Transfer

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.