On Thu, Apr 06, 2006 at 07:00:32AM -0400, Chuck wrote:
> On Friday 21 October 2005 12:23 pm, Chuck wrote:
> > On Friday 21 October 2005 12:12 pm, Herbert Poetzl wrote:
> > > On Fri, Oct 21, 2005 at 06:58:38AM -0400, Chuck wrote:
> > > > i forget.. was it ngnet that would support a few hundred ip addys in a
> > > > guest?
> > > >
> > > > i have a few big machines i cant move over until it can efficiently
> > > > support several hundred ip addys (minimum a /24) ... if ngnet is the
> > > > answer im gonna try to raise some funding from my boss .. no promises
> > > > as he does not let go easily.. :D
> > >
> > > hehe, well, ngnet will provide that indeed,
> > > but for a quick and dirty hack you can raise
> > > the limit from the current 16 to something
> > > higher, but you should be aware that the
> > > current implementation will slow down with
> > > every ip address you add ...
> >
>
> does anyone have some facts about how slow this would get with 130
> or 140 ip addys added to a current vserver? is it just measurable or
> is it visible? unfortunately this mail server is very busy so i am
> extremely hesitant to try this.
with the current design, the lookup/checks are linear
so, you can calculate like this:
there is a minimal general overhead, let's say 2
checks worth on every action
there will be so many checks as are required to
find a match, so roughly N/2 checks per bind,
connect, whatever ...
so with N ips assigned, you will get (N/2)+2
checks, which will give you:
N=1 : 2.5
N=8 : 6.0 ~ 2.4 times slower
N=16 : 10.0 ~ 4.0 times slower
N=256 : 130.0 ~ 52.0 times slower
on those specific checks ...
btw, this will change in the near future, as we
will switch to something of log(N) order, which
should eliminate those overheads
HTH,
Herbert
>
> ----
>
> Chuck
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Received on Mon Apr 10 19:11:21 2006