On Apr 23, 2007 15:04 +0530, Kalpak Shah wrote: > On Mon, 2007-04-23 at 12:49 +0530, Karuna sagar K wrote: > > The tool estimates the cross-chunk references from an extt2/3 file > > system. It considers a block group as one chunk and calcuates how many > > block groups does a file span across. So, the block group size gives > > the estimate of chunk size. > > > > The file systems were aged for about 3-4 months on a developers laptop. > > With a blocksize of 4KB, a block group would be 128 MB. In the original > Chunkfs paper, Valh had mentioned 1GB chunks and I believe it will be > possible to use 2GB, 4GB or 8GB chunks in the future. As the chunk size > increases the number of cross-chunk references will reduce and hence it > might be a good idea to present these statistics considering different > chunk sizes starting from 512MB upto 2GB. Also, given that cross-chunk references will be more expensive to fix, I can imagine the allocation policy for chunkfs will try to avoid this if possible, further reducing the number of cross-chunk inodes. I guess it should be more clear whether the cross-chunk references are due to inode block references, or because of e.g. directories referencing inodes in another chunk. Also, is it considered a cross-chunk reference if a directory entry is referencing an inode in another group? Should there be a continuation inode in the local group, or is the directory entry itself enough? Cheers, Andreas -- Andreas Dilger Principal Software Engineer Cluster File Systems, Inc. - To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
