On Sun, Feb 15, 2009 at 12:37 PM, Robert Milkowski <mi...@task.gda.pl> wrote:
> Hello Peter,
>
> Friday, February 13, 2009, 10:41:54 AM, you wrote:
>
> PT> I'm moving some data off an old machine to something reasonably new.
> PT> Normally, the new machine performs better, but I have one case just now
> PT> where the new system is terribly slow.
>
> PT> Old machine - V880 (Solaris 8) with SVM raid-5:
>
> PT> # ptime du -kds foo
> PT> 15043722        foo
>
> PT> real        6.955
> PT> user        0.964
> PT> sys         5.492
>
> PT> And now the new machine - T5140 (latest Solaris 10) with ZFS striped
> PT> atop a bunch of 2530 arrays:
>
> PT> # ptime du -kds foo
> PT> 15343120        foo
>
> PT> real     2:55.210
> PT> user        2.559
> PT> sys      2:05.788
>
> PT> It's not just du; a find on that directory is similarly bad.
>
>
> Maybe you have some extra tuning on the old server like increased
> DNLC? I would check how many IOs (if any) you are doing during find
> (not a 1st run of course)
>
> On the other hand your find/du will depend mostly on a single thread
> performance and as you can see above you spending relative high
> percentage on CPU and your T2+ will most probably deliver less single
> thread performance than your V880.

I know that. But 3 minutes against 6 seconds?

The thing is, it's just this one set of data that's slow - I've not noticed this
performance falling off a cliff with all the other data that has been moved.

(OK, there could be other datasets that have issues. But most of them don't
and this one is obiously stuck in molasses.)

-- 
-Peter Tribble
http://www.petertribble.co.uk/ - http://ptribble.blogspot.com/
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