On Thu, 2007-08-16 at 13:44 +0200, Bernd Schubert wrote: > Hi, > > on our test-cluster I managed to get a very fragmented filesystem (e2fsck > reports about 9%), mb_history returns a cr value of 5. The documentation says > that "3 – fs is very fragmented (worst at resource consumption)", but it > doesn't tell what 5 means. May I assume 5 is even worse than 3? > > So no the question is what to do about this fragmention? On our test cluster > with 100% garbage this is not a problem, but on a customer system it > certainly is. There was an old ext2 defrag program, would it be possible to > extent this to support journal and extents data? Where can I find some > documentation about the ldiskfs format (ext3 + extents)? I would like to know > which blocks need to be moved.
Is the filesystem filled with lots of small files? Are you working with the latest mballoc? It is supposed to be very good at avoiding fragmentation. To know the on-disk layout of the blocks belonging to a specific file, you can use the FIEMAP patches available in bug 10555. (use the ext3 patch and filefrag). CFS is also working on a free space defragmentor (bug 10827) which should be able to solve such problems. Thanks, Kalpak. > > Thanks, > Bernd > _______________________________________________ Lustre-discuss mailing list [email protected] https://mail.clusterfs.com/mailman/listinfo/lustre-discuss
