From mboxrd@z Thu Jan 1 00:00:00 1970 From: Hans Reiser Subject: Re: Calling stat with millions of files Date: Tue, 08 Jun 2004 15:10:27 -0700 Message-ID: <40C63953.2040603@namesys.com> References: <40C5E92D.2090101@namesys.com> <1086712717.10973.122.camel@watt.suse.com> <40C5EDAE.6000707@namesys.com> <1086713475.10973.125.camel@watt.suse.com> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Return-path: list-help: list-unsubscribe: list-post: Errors-To: flx@namesys.com In-Reply-To: List-Id: Content-Type: text/plain; charset="us-ascii"; format="flowed" To: Ross Skaliotis Cc: reiserfs-list@namesys.com Ross Skaliotis wrote: >>On Tue, 2004-06-08 at 12:47, Hans Reiser wrote: >> >> >>>really afford to do it just for you, sorry. >>> >>> >>>>You'll get better results with the new block allocator in 2.6.7-rcX-mm, >>>>but in the end the stat information for the file isn't horribly close to >>>>the directory entries, and performance won't be perfect. >>>> >>>>Hans, I thought reiser4 was going to be good at this kind of thing? >>>> >>>> >>>> >>>> >>>what in reiser4 optimizes accesses to hard links to files whose stat >>>data is stored in other directories? Maybe the stat data being stored >>>near other stat data instead of near file bodies will help,. Hmmm. >>>Could be, have to try it to see. >>> >>> >>He said above that it creates hard links "when it can", not sure what >>percentage of the time this actually happens. >> >> > >Most files have several hard links. Common files shared between many >backed up computers (windows system files, etc.) can have up to 500 hard >links. > > > >>hardlinks destroy locality of reference for stat data, this is probably >>your problem. >> >> > >So this would be a problem with any filesystem, right? I don't understand >filesystems nearly as well as others on this list, but am I correct in >assuming the stat data would stay "near" the original file? If I can make >my backup system only need to stat original files (which may have hard >links linked to _them_) would my performance issues go away? > > In reiser4 it would probably cure it, probably not in reiser3, though it might help, and I could be wrong.... >Thanks and sorry for my ignorance, > >-Ross > > > >