Jeff Bonwick <jeff.bonw...@sun.com> writes: >> > Yes, I made note of that in my OP on this thread. But is it enough to >> > end up with 8gb of non-compressed files measuring 8gb on >> > reiserfs(linux) and the same data showing nearly 9gb when copied to a >> > zfs filesystem with compression on. >> >> whoops.. a hefty exaggeration it only shows about 16mb difference. >> But still since zfs side is compressed, that seems like quite a lot.. > > That's because ZFS reports *all* space consumed by a file, including > all metadata (dnodes, indirect blocks, etc). For an 8G file stored > in 128K blocks, there are 8G / 128K = 64K block pointers, each of > which is 128 bytes, and is two-way replicated (via ditto blocks), > for a total of 64K * 128 * 2 = 16M. So this is exactly as expected.
All good info thanks. Still one thing doesn't quite work in your line of reasoning. The data on the gentoo linux end is uncompressed. Whereas it is compressed on the zfs side. A number of the files are themselves compressed formats such as jpg mpg avi pdf maybe a few more, which aren't going to compress further to speak of, but thousands of the files are text files (html). So compression should show some downsize. Your calculation appears to be based on both ends being uncompressed. _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
