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Home > Success Center > Serv-U Managed File Transfer & Serv-U FTP Server > Serv-U - Knowledgebase Articles > Enable or use real-time transfer compression

Enable or use real-time transfer compression

Updated May 2, 2017


This article provides information on compression and how to use it.

Compression is a method of reducing a given amount of data.


All Serv-U versions


Compression and Serv-U

For easy transfers of large files, both the Serv-U File Server and the FTP Voyager software includes full support for compression across all file transfer protocols. Compression is a method of reducing a given amount of data. It allows Serv-U to receive a large amount of data that takes less time to be transmitted over the Internet because its compressed size is less than its normal size, allowing for more effective use of bandwidth. Compression is supported on all file transfer protocols used by Serv-U.


The MODE command in the FTP and FTPS protocols enables clients and servers to communicate in detail about the type of compression that will be used during the connection. There are nine levels of compression ranging from the following:

  • low-compression
  • low-CPU usage to high-compression
  • high-CPU usage

The level of compression is determined by the client, and most clients compress at level six for a solid balance between compression and overall performance.


SFTP over SSH2 uses a native form of a built-in compression that is negotiated during the initial SSH connection. This compression is effective and does not need to be configured in any way.

Like SFTP, the HTTP and HTTPS protocols support native compression. It does not permit any customization of compression settings.

Compression Settings in FTP Voyager

Compression is enabled in FTP Voyager by default.

To change FTP Voyager compression settings:

  1. Start FTP Voyager.
  2. Select the preferred FTP Site Profile or create a new one.
  3. Select Advanced.
  4. Click Connection > Compression.
  5. Select the preferred compression option. Press F1 or the Help button for complete details.

Note: Not all FTP servers and clients support this capability. The FTP Voyager and Serv-U compress transfers very well together.



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