On Wed, 2003-07-02 at 14:53, Hans Reiser wrote: > >This is called ordered data mode, and exists on ext3 and also reiserfs with > >Chris Mason's patches. Under normal usage it shouldn't change performance > >compared to writeback data mode (which is what reiserfs does by default). > > > It had some impact, I forget exactly how much, maybe Chris can > resuscitate his benchmark of it? >
The major cost of data=ordered is that dirty blocks are flushed every 5 seconds instead of every 30. The journal header patch in my experimental data logging directory changes things so that only new bytes in the file are done in data=ordered mode (either adding a new block or appending onto the end of the file). This helps a lot in the file rewrite tests. -chris
