2012/3/11 Ted Ts'o <tytso@xxxxxxx>: > > Well, my goal in proposing this optimization is that helps for the > "medium size" directories in the cold cache case. The ext4 user who > first kicked off this thread was using his file system for an SVN > server, as I recall. I could easily believe that he has thousands of > files; maybe even tens of thousands of files in a directory. But that > probably still fits in 256k, or at best 512k worth of directory blocks. > That was not a SVN server. It was a build host having checkouts of SVN projects. The many files/dirs case is common for VCS and the SVN is not the only that would be affected here. AFAIR git.kernel.org was also suffering from the getdents(). Same applies to commercial products that are heavily stuffed with many files/dirs, e.g. ClearCase or Synergy. In the second one case we are running on XFS for a longer while and I must say that this was a huge improvement mostly on backup times (where a dump of Informix and the whole filesystem is ordinary compressed in tarball). A medium size you are referring would most probably fit into 256k and this could be enough for 90% of cases. Large production system running on ext4 need backups thus those would benefit the most here. -Jacek -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
