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Re: LoadBalancing products: Foundry ServerIron

  • From: tony bourke
  • Date: Wed Jul 05 23:55:23 2000

Part of the Foundry GSLB (Global Server Load Balancing) solution is BGP
based, as well as DNS based, depending on what you want to implement.

The problem with DNS is that it doesn't work 100% in case of one
location's failure

The problem with BGP is route injection is that its very complicated to
implement, and I havn't seen it used at all.

Most load balancing products employ some sort of DNS based method for
global distribution, and many offer something on top of this to
compenstate for DNS's shortcomings.

GSLB is still rapidly evolving, so 6 monthes from now there will be
several other solutions available as well.

Tony


On Wed, 5 Jul 2000, Peter Francis wrote:

> 
> The Foundry solution (ServerIron) is not BGP based.
> 
> It is a DNS-based solution that uses a round-trip-time metric (calculated based on TCP syn/ack from client to server by the ServerIron on a per connection basis).
> 
> The two down-sides of a DNS based solution are both caused by the fact that client source IPs are not contained in the request that comes from the client DNS resolver:
> 
> 1] persistant connections must be managed on each real server.
> 
> 2] client's whose IP is not within the same netblock (defaults to /20, tuneable) as DNS resolver do not get the benefit of RTTmetrics.
> 
> 
> Peter
> 
> 
> 
> 
> At 6:10 PM -0400 7/5/00, Dmitri Krioukov wrote:
> >the major disadvantage of the foundry (bgp)
> >solution is longer prefix injection.
> >
> >the major problem with the dns-based solutions is
> >that they're not topology-aware (-> suboptimal
> >routing). attempts to make dns smart lead to
> >rather awkward reverse pinging configurations
> >and proprietary protocols running between load
> >balancers. (there was also rfc2052 by paul vixie
> >but it required modification of dns clients.)
> >
> >there is also the "triangle data flow" solution,
> >which is broken by cef...
> >
> >i'm in the process of preparing an overview
> >of the available techniques along with introduction
> >of a new one, which solves a lot of headaches.
> >it requires a feature set that is not available
> >on any of the currently existing lb platforms,
> >hence, for testing, i had to develop one using
> >open source (i chose linux to make it fast (it
> >had almost all bits in place -- check
> >http://www.linuxvirtualserver.org/)).
> >--
> >dima.
> >
> >> -----Original Message-----
> >> From: [email protected] [mailto:[email protected]]On Behalf Of
> >> tony bourke
> >> Sent: Wednesday, July 05, 2000 2:11 PM
> >> To: Jeremiah Kristal
> >> Cc: [email protected]
> >> Subject: Re: bad idea?
> >>
> >>
> >>
> >> actually, Foundry has a global solution based on BGP, check them out.
> >>
> >> There is a load-balancing mailing list, which addresses such issues.
> >>
> >> http://vegan.net/lb is the info to sign up.
> >>
> >> Tony
> >>
> >> On
> >> Wed, 5 Jul 2000, Jeremiah Kristal wrote:
> >>
> >> >
> >> > Given a small, globally routable netblock to be used for front-end web
> >> > servers, and a strong aversion for using DNS for any type of load
> >> > balancing, would it be reasonable to build two identical servers farms
> >> > with the same public IP addresses and rely on the BGP sessions with the
> >> > hosing providers to remove one advertisement in the event of a problem?
> >> > I've been looking at ways to ensure that the webservers are always
> >> > available, short of building a network connecting hosting facilities.
> >> >
> >> > Jeremiah
> >> > being a customer stinks
> >> >
> >>
> >> -------------- -- ---- ---- --- - - - -  -  -- -  -  -  -   -     -
> >> Tony Bourke				[email protected]
> >>
> >>
> >>
> >>
> 
> 

-------------- -- ---- ---- --- - - - -  -  -- -  -  -  -   -     -
Tony Bourke				[email protected]