RE: [load balancing] Global Load Balancing

From: Udi Segall <UdiS [izzat] Radware.com>
Date: Tue Oct 03 2006 - 11:38:17 EDT

James,

 

I would also suggest that you would look at Radware GSLB solution, which
enables you to optimize sub-optimal site selections made by DNS
redirection, with HTTP redirection. This mechanism enables you also to
overcome known limitations of DNS redirections such as DNS caching and
lack of persistency identifier in DNS requests.

 

Let me know if you want more information.

 

Regards,

 

Udi

 

________________________________

From: owner-lb-l@vegan.net [mailto:owner-lb-l@vegan.net] On Behalf Of
Richard Golding
Sent: Tuesday, October 03, 2006 12:41 PM
To: lb-l@vegan.net
Subject: RE: [load balancing] Global Load Balancing

 

James,

 

Global Server Load Balancing works by making the Load Balancing device
the authorative name server for the domain names that it is load
balancing. The Load Balancing device typically returns DNS responses
with very low Time to Live which in effect forces downstream DNS servers
to always query the Load balancer. (if DNS server honours the low TTL).

 

The Load Balancer will return an intelligent DNS response (i.e. will
always return a DNS address that is healthy and reachable by the
client).

 

The Alteon also has a feature whereby if a site to which the client has
been served goes down the Alteon will send a HTTP redirect to another
site which it knows to be healthy.

 

Hope that helps?

 

Regards,

 

Richard

        -----Original Message-----
        From: owner-lb-l@vegan.net [mailto:owner-lb-l@vegan.net] On
Behalf Of James Jonah
        Sent: 03 October 2006 11:22
        To: lb-l@vegan.net
        Subject: Re: [load balancing] Global Load Balancing

        Marcel,
        
        DNS resolving only takes into account client's DNS server. How
can this give me more flexibility? Clients have multiple DNS servers
listed and can use them. So at any given time (even between the same
session) client can query different DNS server so ultimately the query
to global load balancer can come from a different server and give the
same client different result. How can this give me more flexibility? I
can end up at different location and break a session.
        
        
        

        On 10/3/06, Marcel Derksen <marcel@maderco.nl> wrote:

        James,
        
        The Nortel and F5 Global Load balancers work based upon DNS
resolving.
        Basicly what they do is work as an DNS resolver for the hostname
you
        want to global load balance. Based upon different parameters you
can
        specify they will answer the dns-request with the most healthy
site.
        
        This will give you more flexibilty then solution that use
        http-redirect.
        
        Hope this helps a bit.
        
        Marcel.
        
> On Mon, 2 Oct 2006 18:34:28 -0400, "James Jonah" <
jamesjonah@gmail.com>
> said:
> > Hello experts,
> >
> > What are my options when it comes to global load balancing?
> >
> > Simple DNS is not enough as we all know the client's server
is the one
> > doing
> > the actual query and if client does query different server
it can end up
> > on
> > a different location where it doesn't have session.
> >
> > HTTP redirect (if it is HTTP protocol) is an option to get
me back to the
> > original server, but then I am stuck with URL change based
on site. If
> > changing URL is not an option, how can a load balancer
handle such a
> > request? Any major load balancers can do that at all or they
all work on
> > URL
> > (HTTP redirect) when it comes to global persistency issue?
> >
> > Thanks!
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Received on Tue Oct 3 11:38:29 2006

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