Re: [PATCH fio] engines: Add Network Block Device (NBD) support.

["Richard W.M. Jones" <rjones@redhat.com>]

On Fri, Apr 19, 2019 at 10:27:49AM +0100, Sitsofe Wheeler wrote:
> On Thu, 18 Apr 2019 at 15:10, Richard W.M. Jones <rjones@redhat.com> wrote:
> > If there are multiple jobs (files?) should these be striped over the
> > block device?
> 
> It depends on how you define the job. If you were to just copy the job
> and give it a new name it would likely just overlap the first job
> (because it's just going to do the same thing at the same time). You
> would need to use something like numjobs
> (https://fio.readthedocs.io/en/latest/fio_doc.html#cmdoption-arg-numjobs
> ) offset_increment
> (https://fio.readthedocs.io/en/latest/fio_doc.html#cmdoption-arg-offset-increment
> ) and a workload that skipped (e.g. rw=write:12k -
> https://fio.readthedocs.io/en/latest/fio_doc.html#cmdoption-arg-readwrite
> ) to achieve striping.

I meant should the NBD engine stripe the jobs.  Something like: job 0
gets to use the first <size> bytes of the NBD device, job 1 gets to us
the next <size> bytes, etc.  (Or actually striped/interleaved using a
smaller block size).  In other words it would be something hidden
inside the NBD engine and not "visible" to fio.

Thanks for the rest of the email - very helpful.

Rich.

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