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On Thu, 2005-04-28 at 10:26, orpheus@xxxxxxxxxxxxxxxxxxxx wrote:
> On Thursday 28 April 2005 15:43, Bruce Richardson wrote:
> > On Thu, Apr 28, 2005 at 02:52:42PM +0200, orpheus@xxxxxxxxxxxxxxxxxxxx
> wrote:
> > > Hello,
> > >
> > > we are using now our LVS in DR configuration. But we are considering to
> > > move to NAT. Can somebody tell me disadvantages and advantages (securit,
> > > connection handling, and..... ) of NAT configuration and if it is hard
> > > (or how to, easy) to change it.
> >
> > The advantages of NAT are that it doesn't require any special settings
> > (e.g. arp suppression on the application servers), that you can
> > reconfigure which virtual ip is associated with a back-end server
> > by modifying the director alone and that it's easier to do connection
> > tracking. The main disadvantage is that all traffic goes through the
> > director, making the director a potential bottleneck.
>
> first, thanks for answer
> do you have some recommendations on hardware used for that?
> I think 2 eth cards are real minimum for that, but would it help to have 3 or
> 4 ? How it is with CPU and memory. Right now it is PIII 700MHz
> (735.315MHz :) ) with 512MB of memory with one eth card.
NAT is definitely simpler to implement than DR.
However you can achieve higher throughput with DR since packets are only
forwarded to the real servers, unchanged.
Please take a look at these documentations:
* Performance Evaluation of Linux Virtual Server
http://www.usenix.org/events/lisa2001/tech/full_papers/orourke/orourke_html/
* Horms LVS White Paper
http://www.ultramonkey.org/papers/lvs_tutorial/html/
What kind of throughput are you looking for?
Sam
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