On Sun, Dec 23, 2018 at 12:24:02AM +0000, Paul Jones wrote: > > IMHO the more pertinent question is : > > > > If a file has portions which are not easily compressible does that imply all > > future writes are also incompressible. IMO no, so I think what will be > > prudent > > is remove FORCE_COMPRESS altogether and make the code act as if it's > > always on. > > > > Any opinions? > > > That is a good idea. If I turn on compression I would expect everything > to be compressed, except in cases where there is no size benefit.
I expect that the vast majority of files consist of blocks of similar compressibility. Thus, finding a block that fails to compress strongly suggests other blocks are either incompressible as well or compress only minimally. Refusing to waste time, electricity and fragmentation in such case is a good default, I think. But, if you believe this should be changed, there's an easy experiment you can try: for all files on your filesystem, chop every file into 128KB pieces and compress each of them with your chosen algorithm. Noting the compressed size of every block in a file that had at least one block fail to compress would give us some data. Meow! -- ⢀⣴⠾⠻⢶⣦⠀ ⣾⠁⢠⠒⠀⣿⡁ Ivan was a worldly man: born in St. Petersburg, raised in ⢿⡄⠘⠷⠚⠋⠀ Petrograd, lived most of his life in Leningrad, then returned ⠈⠳⣄⠀⠀⠀⠀ to the city of his birth to die.
