>aufs2-util is essentially necessary, especially these files. > >(from the aufs2-util README) > (...) >They are always invoked at mount/remount/unmount time. >The main purpose of /sbin/mount.aufs is, >- maintain /etc/mtab >- maintain the aufs pseudo-link (by calling /sbin/auplink) > >If you don't install /sbin/mount.aufs, then the aufs line in your >/etc/mtab will be incorrect, and you may loose the aufs pseudo-link. >/sbin/auplink is called by /sbin/umount.aufs too. > >If you don't know what the aufs pseudo-link is, then refer to the aufs >manual in detail. >Additional information, > >(from linux/Documentation/filesystems/aufs/design/02struct.txt) >Pseudo-link >---------------------------------------------------------------------- >Assume "fileA" exists on the lower readonly branch only and it is >hardlinked to "fileB" on the branch. When you write something to fileA, >aufs copies-up it to the upper writable branch. Additionally aufs >creates a hardlink under the Pseudo-link Directory of the writable >branch. The inode of a pseudo-link is kept in aufs super_block as a >simple list. If fileB is read after unlinking fileA, aufs returns >filedata from the pseudo-link instead of the lower readonly >branch. Because the pseudo-link is based upon the inode, to keep the >inode number by xino (see above) is important. > >All the hardlinks under the Pseudo-link Directory of the writable >branch >should be restored in a proper location later. Aufs provides a utility >to do this. The userspace helpers executed at remounting and unmounting >aufs by default. >---------------------------------------------------------------------- >And >http://www.mail-archive.com/aufs-users@lists.sourceforge.net/msg02639.html > >If you don't care about /etc/mtab and the pseudo-link, you can >uninstall >aufs2-util. Otherwise, just install it. > > >Generally readdir(3) in libau.so runs faster than readdir in aufs >kernel-space, particulary for the huge dir.
Thank you very much for the explanation. Now it is much more clear :) ------------------------------------------------------------------------------ This SF.net email is sponsored by Sprint What will you do first with EVO, the first 4G phone? Visit sprint.com/first -- http://p.sf.net/sfu/sprint-com-first
