Re: ext3 performance issue with a Berkeley db application

[Greg Louis <glouis dynamicro on ca>]

On 20030204 (Tue) at 1558:28 +0000, Stephen C. Tweedie wrote:
> Hi,
> 
> On Tue, 2003-02-04 at 12:41, Matthias Andree wrote:
> 
> > > ext3 is making it write much _more_ data.  Due to the 5-second commit,
> > > the application's redirtying and an ext3 gremlin.
> 
> > So this means we write more data because ext3 commits quicker than the
> > other file systems I tested and has less chance to kill old write
> > requests that are overwritten because they were already flushed to disk?
> > Then we really won't have much choice except quenching our overwrites as
> > far as reasonable and try to improve locality of our operations.
> 
> Or using data=writeback, or specifying a longer commit interval.

I tried data=ordered,commit=120 and was surprised to find that it
actually took longer than with the default 5 seconds; 9-and-a-half
minutes to run Matthias's simbf program, as opposed to about
seven-and-a-quarter. Using data=writeback certainly helps; that run
takes eighteen seconds.
 
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