> Wouldn't ZFS's being an integrated filesystem make it easier for it to > identify the file types vs. a standard block device with a filesystem > overlaid upon it?
I'm not sure. I would think that most applications are going to use the POSIX layer where there's no separate API for filetypes. Every file is "just" a bytestream. I don't see that ZFS gives you any more information about a file's purpose or use. > I read in another post that with compression enabled, ZFS attempts to > compress the data and stores it compressed if it compresses enough. As far > as identifying the file type/data type how about: > 1.) ZFS block compression system reads the ZFS file table to identify which > blocks are the beginning of files (or for new writes, the block compression > system is notified that file.ext is being written on block #### (e.g. block > 9,000,201). While it is "block" compression, it is filesystem blocks, not disk blocks. > An approach for maximal compression: > The algorithm selection could be > 1.) attempt to compress using BWT, store compressed if BWT works better > than no compression > 2.) when CPU is otherwise idle, use 10% of spare cpu cycles to "walk the > disk", trying to recompress each block with each of the various supported > compression algorithms, ultimately storing that block in the most space > efficient compression format. It would be interesting to determine how this could fit in with snapshots. From one point of view this is the same data, just compressed differently. So you might want the old snapshots to point to it. From another point of view this data has changed, so the snapshots should point to only the original form of the data. Would this be worthwhile even if you had to allocate more space because it could not be shared by older snapshots? -- Darren Dunham [EMAIL PROTECTED] Senior Technical Consultant TAOS http://www.taos.com/ Got some Dr Pepper? San Francisco, CA bay area < This line left intentionally blank to confuse you. > _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
