On Mon, 2011-09-19 at 10:53 +0800, Li Zefan wrote: > Maciej Marcin Piechotka wrote: > > I've noticed that: > > > > - with x86-64 Fedora 15 DVD install images: > > - du -sh <ROOT VOLUME> was 36 GB > > - btrfs df | grep -i data have shown over 40 GB used > > - without > > - du -sh <ROOT VOLUME> is 34 GB > > - btrfs df | grep -i data have shown less then 34 GB used > > > > It seems that iso files are considered compressable while they may not be (and penalty is severe - 3x). > > > > With compress option specified, btrfs will try to compress the file, at most > 128K at one time, and if the compressed result is not smaller, the file will > be marked as uncompressable. > > I just tried with Fedora-14-i386-DVD.iso, and the first 896K is compressed, > with a compress ratio about 71.7%, and the remaining data is not compressed. > > -- > Li Zefan Just a question from person who don't know how btrfs operates - what if the beginning of file is well compressable and the rest is not? In any case the compression was my uneducated guess where is missing 4GB. Regards -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
