On Mon, 2008-03-31 at 13:18 +0200, Sebastian Reitenbach wrote: > Hi Nicolas, > > Nicolas KOWALSKI <niko@xxxxxxxxxxxxxxxxx> wrote: > > "Sebastian Reitenbach" <sebastia@xxxxxxxxxxxxxxxxxxxx> writes: > > > > > installhost2:~ # time ls -la /mnt/index/ | wc -l > > > 500005 > > > > > > real 2m41.015s > > > user 0m4.568s > > > sys 0m6.520s > > > > > > > > > installhost2:~ # time ls -la /mnt/noindex/ | wc -l > > > 500005 > > > > > > real 0m10.792s > > > user 0m3.172s > > > sys 0m6.000s > > > > > > I expected the dir_index should speedup this a little bit? > > > I assume I'm still missing sth? > > > > I think the point of dir_index is "only" to quickly find in a large > > directory a file when you _already_ have its name. > > > > The performance of listing is not its purpose, and as you noted it, > > even makes performance worse. > > ah, that would explain what I've seen here. > > after reading your answer, I found this older mail in the archives: > http://osdir.com/ml/file-systems.ext3.user/2004-09/msg00029.html See also the https://www.redhat.com/archives/ext3-users/2007-October/msg00011.html thread I started about slow directory traversal. That includes reference to a library one can load to speed things up sometimes; I was never clear on exactly how to build and use it (I would need to get a daemon to use the library) and my only test failed. I later learned that tar, my test program, doesn't use the right system calls to benefit. > > So everything seems to depend on how the application is using the > filesystem. > Picking a single given file might be faster than with a plain ext3, but > scanning and opening all files in a directory might become slower. I wanted > to use the dir_index for some partitions, like for cyrus imap server, and Careful: it was problems backing up a cyrus imap spool that prompted my question. I just ran a cyrus backup and it took 35 hours. Incremental backups take 3. > for some other applications. I think I have to benchmark the applications, > to see whether they get a speed gain of the dir_index or not. > > kind regards > Sebastian > > > > _______________________________________________ > Ext3-users mailing list > Ext3-users@xxxxxxxxxx > https://www.redhat.com/mailman/listinfo/ext3-users -- Ross Boylan wk: (415) 514-8146 185 Berry St #5700 ross@xxxxxxxxxxxxxxxx Dept of Epidemiology and Biostatistics fax: (415) 514-8150 University of California, San Francisco San Francisco, CA 94107-1739 hm: (415) 550-1062 _______________________________________________ Ext3-users mailing list Ext3-users@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/ext3-users
