I usually use pbzip2 which is multi-threaded bzip2. As for efficiency, gzip -9 uses a 32kb window while bzip2 -9 uses a 900kb window. This plus other improveme

I usually use pbzip2 which is multi-threaded bzip2. As for efficiency, gzip -9 uses a 32kb window while bzip2 -9 uses a 900kb window. This plus other improvements is why bzip2 beats gzip. > I'd say the more time you spend on compression, the less overall time you're looking at. That turns out not to be the case. For example xz (-9 uses a 65MB window) does indeed result in better compression. However it isn't multi-threaded and uses considerably more cpu time. The extra time taken is beaten by using pbzip2 which can start the upload sooner. 7z does allow multi-threading if you can navigate it's command line options. BTW here is a quick test. I have a json file that is 8.1GB. 442MB 3m12s single threaded gzip -9 309MB 23m single threaded bzip2 -9 326MB 25m single threaded xz -9