On Tue, Aug 14, 2012 at 3:55 PM, Alecks Gates <aleck...@gmail.com> wrote:
> On Tue, Aug 14, 2012 at 12:50 PM, Michael Hampicke <gentoo-u...@hadt.biz> > wrote: > > Am 14.08.2012 19:42, schrieb Volker Armin Hemmann: > >> Am Dienstag, 14. August 2012, 13:21:35 schrieb Jason Weisberger: > >>> Sure, but wouldn't compression make write operations slower? And > isn't he > >>> looking for performance? > >> > >> not really. As long as the CPU can compress faster than the disk can > write > >> stuff. > >> > >> More interessting: is btrfs trying to be smart - only compressing > compressible > >> stuff? > >> > > > > It does do that, but letting btrfs check if the files are already > > compressed, if you know, that they are compressed, is a waste of cpu > > cycles :) > > > > Also look into the difference between compress and compress-force[0]. > I wonder how much overhead checking whether or not to compress a file > costs. I use mount options similar to Helmut and get great results: > defaults,autodefrag,space_cache,compress=lzo,subvol=@,relatime > > But most of my data is compressible. Compression makes such a huge > difference, it surprises me. Apparently on this Ubuntu system it > automatically makes use of all files on / as a subvolume in "@". > Interesting. > Huge difference, how? Could we see some bonnie++ comparisons between the various configurations we've discussed for ext4 and btrfs? Depending on the results, it might be getting time for me to take the plunge myself. -- :wq
