On Mon, 2007-03-19 at 17:50 -0400, James Cloos wrote: > I've had my laptop's / on jfs for a while now. > > I notice that many directories become excessively large after > some use. As an example: > > ,----[ ls -lsd /etc /tmp ] > | 468 drwxr-xr-x 297 root root 430080 Mar 19 17:12 /etc > | 50016 drwxrwxrwt 122 root root 50872320 Mar 19 17:40 /tmp > `---- > > Compare that with: > > ,----[ /bin/ls /etc | wc -l ] > | 607 > `---- > ,----[ /bin/ls /tmp | wc -l ] > | 1251 > `---- > > This happens with any dir that has overturn. > > Rsync(1)ing the dir creates a new one that is much smaller. In the > case of /etc it ended up taking only two fs blocks: > > ,----[ ls -lsd /BAK/etc ] > | 36 drwxr-xr-x 99 root root 8192 Mar 19 17:48 /ETC/etc > `---- > > I presume it has something to do with extents?
No. It's a data structure I call the directory index. It's associates a fixed position with each entry in the directory, so that directory traversals resume at the right point even when changes are made to the b +-tree. (When jfs was young, rm -rf would fail to remove everything in the directory because the position within the directory got lost.) It slowly grows every time a file is created, but does not shrink when files are deleted. It is reset to zero if a directory is completely emptied, but that doesn't usually happen. I can look into a fix, either some mechanism to reuse old positions, or something to remove the directory index and rebuild it when too much space is wasted. > Is there any way to prevent this growth? Not currently. I can look into a fix, either some mechanism to reuse old positions, or something to remove the directory index and rebuild it when too much space is wasted. > -JimC -- David Kleikamp IBM Linux Technology Center ------------------------------------------------------------------------- Take Surveys. Earn Cash. Influence the Future of IT Join SourceForge.net's Techsay panel and you'll get the chance to share your opinions on IT & business topics through brief surveys-and earn cash http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV _______________________________________________ Jfs-discussion mailing list Jfs-discussion@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/jfs-discussion
