> Matthew Ahrens wrote: > > On Thu, Aug 17, 2006 at 02:53:09PM +0200, Robert Milkowski wrote: > >> Hello zfs-discuss, > >> > >> Is someone actually working on it? Or any other algorithms? > >> Any dates? > > > > Not that I know of. Any volunteers? :-) > > > > (Actually, I think that a RLE compression algorithm for metadata is a > > higher priority, but if someone from the community wants to step up, we > > won't turn your code away!) > > maybe a stupid question: what do we use for compressing dump data on the > dump device? > > Michael
We use LZJB for that, too, which is Jeff's minimal Lempel Ziv, found in usr/src/uts/common/os/compress.c. The major issue here is the small history buffer, since it has to be declared on the stack for purposes of the panic code path. For use with in-kernel CTF, I ported zlib to a general-purpose kernel misc module named "zmod" -- see usr/src/uts/common/zmod/. However, since we only needed decompress I only included that part of the library. So if we want to work on more general-purpose higher quality compression for the kernel, the first step should really be to add the compress portion of zlib to zmod, and then we can interface that to other subsystems that need it. That said, zlib's cpu/time properties may be unsuitable for some of these tasks: it tends to be on the slow side for compression. -Mike -- Mike Shapiro, Solaris Kernel Development. blogs.sun.com/mws/ _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
