For parallel compression that's compatible with xz, you should use [pixz|https://github.com/vasi/pixz] (preferred) or [pxz|http://jnovy.fedorapeople.org/pxz/].  Pxz uses a __lot__ more memory.

Note: when installing on Mac, you may have to first install [libarchive|http://libarchive.github.com/]

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[CategoryComputing.Performance]