On Mon, Feb 4, 2019 at 10:19 PM Nio Wiklund <[email protected]> wrote: : > cat bigfile | parallel --pipe --recend '' -k gzip -9 > bigfile.gz : > The reason why I want this is that I often create compressed images of > the content of a drive, /dev/sdx, and I lose approximately half the > compression improvement from gzip to xz, when using parallel. The > improvement in speed is good, 2.5 times, but I think larger blocks would > give xz a chance to get a compression much closer to what it can get > without parallel. > > Is it possible with with the current code? In that case how?
Since version 2016-07-22: parallel --pipepart -a bigfile --recend '' -k --block -1 xz > bigfile.xz parallel --pipepart -a /dev/sdx --recend '' -k --block -1 xz > bigfile.xz Unfortunately the size computation of block devices only works under GNU/Linux. (That said: pxz exists, and it may be more relevant to use here). /Ole
