On 30 Nov 2008, at 02:59, Bob Friesenhahn wrote: > On Sun, 30 Nov 2008, Ian Collins wrote: > >> What did you expect? A 3GHz Opteron core takes about a minutes to >> attempt to compress a 1GB .mkv file. So your P3 would probably take >> between 5 and 10 minutes. Now move that to the kernel and your >> system >> will crawl. High gzip compressions are only really feasible on fast >> multi-core systems (the compression is threaded). > > The gzip manual pages says that the default compression level for gzip > is -6. Experimentation will show that the compression ratio does not > increase much at -9 so it is not worth it when you are short on time > or CPU.
Would it also help if the blocksize were reduced down from the default (128K?) in the filesystem with gzip compression? It feels like it might - there'd be more (and smaller) blocks being compressed, so more chance of other things being able to happen in between blocks. I stress this is a WAG, but it is an easy variable to alter. Cheers, Chris _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
