====== ZFS - Compression ======

ZFS compression is off by default, but recommended to be used, as the performance gain for typical data is significant.

  * **LZ4**: is a stream algorithm offering extremely rapid compression and decompression, and is a performance win for the majority of use cases.
  * **GZIP**: is the venerable algorithm all Unix-like users know and love.
    * It can be implemented with compression levels 1-9, with increasing compression ratio and CPU usage as levels approach 9. 
    * gzip may be a win for all-text (or otherwise extremely compressible) use-cases, but frequently results in CPU bottlenecks otherwise—use with caution, particularly at higher levels.
  * **LZJB**: is the original algorithm used by ZFS.
    * It is deprecated, and should no longer be used.
    * LZ4 is superior in every metric.
  * **ZLE**: is Zero Level Encoding.
    * It leaves normal data alone entirely, but will compress large sequences of zeroes.
    * Useful for entirely in-compressible datasets (e.g. JPEG, MP4, or other already-compressed formats), since it ignores the in-compressible data, but compresses slack space on final records.