[Lustre-devel] proposal to increase seek in sgpdd_survey

[Eric Barton]

Brian,

> Just for clarification Eric...  Are you advocating num_gaps ==
> num_regions or num_gaps == num_regions-1?  i.e. in a two region test
> should the second region start at 50% of the disk or 100%-$region_size
> so that the last byte of the second region is written to the last byte
> of the disk?
> 
> It seems to me that the first option provides a more "middle of the
> road" (which might correlate to real-world averages more closely)
> average as it only incorporates a seek of half the disk whereas the
> second option provides a more worst case performance result.

Not quite so bothered by that and it gets less intersting with more
regions.  Maybe leave it in as a non-default option, in case it's
a real disk killer.

    Cheers,
              Eric