From mboxrd@z Thu Jan 1 00:00:00 1970 From: Hans Reiser Subject: Re: what do you do that stresses your filesystem? Date: Sun, 05 Jan 2003 11:17:05 +0300 Message-ID: <3E17EA01.1080309@namesys.com> References: <3E06F360.7000708@namesys.com> <3E0D364F.1010008@emageon.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: <3E0D364F.1010008@emageon.com> List-Id: Content-Type: text/plain; charset="us-ascii"; format="flowed" To: Brian Tinsley Cc: ReiserFS Brian Tinsley wrote: > I'm late replying to this one, but I've been on vacation :) > > Any possible optimizations for the following would be beneficial: > * interaction with the Linux NFS server Yes, agreed, especially 0 copy stuff. > > * SMP machines already addressed by reiser4 (but not tested and benchmarked yet) > > * apps like grep, awk, and sed reasonable. > > > Any optimizations for the following application characteristics would > be beneficial: > > * Our applications perform multi-threaded streaming I/O > (network-to-disk and vice versa) with read/write block sizes varying > from 16KB to 64KB; we have files ranging in size from 32KB to 500MB+ > (this top end will likely grow into several GB in the near future). hopefully allocate on flush will optimize that well enough. how many threads? > > * Our directory structure is very broad, but not very deep and files > are stored in leaf nodes only. hopefully reiserfs already does this one well. > > * When a file is created and completely written to disk, it is often > re-read in its entirety at least two times within a couple of minutes. Hopefully current lru algorithms handle this. > > * Our database app performs lots of block-based random I/O and fsyncs > within a dozen or so large files. This we have not given a lot of attention to, and probably some serious study of it is desirable. I hope that we do reasonably well at this, but I can't say that I know that we do. Thanks Brian, this was a good list. > > > > > Hans Reiser wrote: > >> We were discussing how to optimize reiser4 best, and came to realize >> that us developers did not have a good enough intuition for what >> users do that stresses their filesystem enough that they care about >> its performance. >> >> If you just do edits of files it probably does not matter too much >> what fs you use. >> >> Booting the machine seems like one activity that many users end up >> waiting on the FS for. Yes? >> >> Starting up complex and big applications like xemacs and mozilla >> would be another. Yes? >> >> Others? >> >> Hans >> >> PS >> >> reiser4 performance is up a lot recently, and within two weeks I >> think cp -r will have been optimized as much as is worth doing. cp >> -r accesses files in readdir order, and that does indeed seem worth >> optimizing, but soon we will need to optimize more sophisticated >> access patterns than that..... >> >> Hans > > > -- Hans