On Mon, 3 Nov 2008, Robert Milkowski wrote: > > Maybe that's a good one - so if couple of blocks do not compress then > flag it in file metadata and do not try to compress any blocks within > the file anymore. Of course for some files it will be suboptimal so > maybe a dataset option?
This is interesting but probably a bad idea. There are many files which contain a mix of compressable and uncompressable blocks. It is quite easy to create these. One easy way to create such files is via the 'tar' command. If compression is too slow, then another approach is to monitor the backlog and skip compressing blocks if the backlog is too high. Then use a background scan which compresses blocks when the system is idle. This background scan can have the positive effect that an uncompressed filesystem can be fully converted to a compressed filesystem even if compression is enabled after most files are already written. There would need to be a flag which indicates if the block has already been evaluated for compression or if it was originally uncompressed, or skipped due to load. Bob ====================================== Bob Friesenhahn [EMAIL PROTECTED], http://www.simplesystems.org/users/bfriesen/ GraphicsMagick Maintainer, http://www.GraphicsMagick.org/ _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
