Re: no unlink file before write testing

From: Jens Axboe <jens.axboe_at_oracle.com>
Date: Tue, 15 Apr 2008 09:21:06 +0200

On Tue, Apr 15 2008, Zhang, Yanmin wrote:
>
> On Mon, 2008-04-14 at 12:37 +0200, Jens Axboe wrote:
> > On Mon, Apr 14 2008, Jens Axboe wrote:
> > > On Tue, Apr 08 2008, Zhang, Yanmin wrote:
> > > > Jens,
> > > >
> > > > As for write testing, fio chooses to unlink the files before testing.
> > > > I run the testing on many big files, so the file preparation spends
> > > > lots of time. Is it possible to add a new parameter, such like
> > > > nounlinkwrite, to ask fio not to unlink files before testing? Its default
> > > > value could be false.
> > > >
> > > > Current parameter overwrite always recreates the files.
> > >
> > > How about we just change that instead? If the file exists and is big
> > > enough, there's no point in having 'overwrite' recreate the file.
> >
> > That seems to be how overwrite currently behaves (and, anything else
> > would have surprised me).
> >
> > Can you come up with a concrete example that doesn't behave as expected?
> You are right. originally, I was misled by function extend_file. After double-checking
> it, I find caller setup_files has a checking before setting flag FIO_FILE_EXTEND.
>
> How about change below statement in HOWTO from:
>
> overwrite=bool If writing to a file, setup the file first and do overwrites.
>
> to:
>
> ???overwrite=bool If writing to a file and extending the file when setup, overwrites the
> whole file.

I changed it to:

overwrite=bool If true, writes to a file will always overwrite existing
                data. If the file doesn't already exist, it will be
                created before the write phase begins. If the file exists
                and is large enough for the specified write phase, nothing
                will be done.

OK?

-- 
Jens Axboe
Received on Tue Apr 15 2008 - 09:21:06 CEST

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