Reflection for Secure IT Server for Windows > Secure File Transfer > Smart Copy and Checkpoint Resume

Smart Copy and Checkpoint Resume

By default, Reflection for Secure IT supports the following features that help minimize the amount of time and resources spent repeating unnecessary transfer of data.

NOTE:The Secure Shell client must also support this feature.

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.

Automatic Resume of Interrupted File Transfer

Reflection for Secure IT clients connected to Reflection for Secure IT support the ability to 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.

Disabling Smart Copy and Checkpoint Resume

If you want to force a complete transfer every time, you can disable the smart copy and checkpoint resume features. This has the following effects:

  • Existing files are always overwritten.

  • File transfer always starts over after an interruption.

NOTE:Disabling smart copy and checkpoint resume is product-dependent; it affects transfers to and from current versions of all Reflection for Secure IT clients, but does not affect the behavior of all SSH clients.

To disable smart copy and checkpoint resume

  1. From the server console, go to Configuration > Permissions.

  2. Under File Transfer, clear Allow smart copy & resume.