Inline Compression

To facilitate inline compression of files, servedat includes a built-in "zli" package handler.  Compatible clients (from ExpeDat 1.9 or SyncDat 1.1 and later) can request ZLIB compression of file data while it is in transit.

Unlike external packaging plug-ins, the built-in ZLIB compression works on both uploads and downloads.  The data is automatically compressed and decompressed as part of the transfer, so that no extra steps or third-party software are required.

Compression is very CPU intensive.  Data files which are already compressed, encoded, or encrypted, will not benefit from compression.  If the server or client is CPU limited, enabling compression may severely reduce performance.

Compression should only be used on files known to contain compressible data, such as text documents.  Audio, video, pictures, encrypted data, and already compressed archives will not benefit from compression.  If you are on a very fast network, even compressible data may move faster without compression due to the CPU overhead of compressing it.

If you are concerned about the CPU load that may be created by users requesting compression of their files, you can disable servedat compression support using the NoCompression configuration variable or the -Z command line option.

For more additional information about the advantages and disadvantages of compression, see DEI Technical Note 0014.