From mboxrd@z Thu Jan 1 00:00:00 1970 From: Hans Reiser Subject: Re: Resier Fragmentation Effects (was compression vs performance) Date: Fri, 09 Apr 2004 23:09:28 -0700 Message-ID: <40778F98.8030401@namesys.com> References: <3DF9165145FACB4C96977FF650C1E9040C469DBF@its-mail1.its.corp.gwl.com> <40763A44.4040107@namesys.com> <1081534415.16461.10.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: <1081534415.16461.10.camel@watt.suse.com> List-Id: Content-Type: text/plain; charset="us-ascii"; format="flowed" To: Chris Mason Cc: "Burnes, James" , Stewart Smith , Tom Vier , Scott Young , reiserfs-list@namesys.com Chris Mason wrote: >On Fri, 2004-04-09 at 01:53, Hans Reiser wrote: > > >>Burnes, James wrote: >> >> >> >>>I thought nearly all filesystems designed since Berkeley FFS were nearly >>>immune to fragmentation problems. >>> >>>After reading the following analysis at Harvard, it seems that >>>fragmentation is still a problem. >>> >>>http://www.eecs.harvard.edu/~keith/research/tr94.html >>> >>> >>> >>> >>> >>Yeah, I wish I had read this in 94. V3 suffers from the same problems >>as FFS does as described in the abstract (all that I read, sorry about >>that, I really am a bit busy, so unless someone suggests I should read >>more.... ) . V4 cures it though. >> >> > >I put out some patches last week that try to deal with this in v3. > Describe the algorithmic changes please. > Take >a look through the archives for mail from me. > >The v3 patches are an attempt to do better under common workloads. I >think they are a big improvement, and I doubt there's much more that can >(or should) be done beyond simple tweaking. > >v4 does a better job, and even if it doesn't, it should at least have >enough info in the metadata such that any problems can be fixed. > >-chris > > > > > > -- Hans