load balancing

Geoff Wong <>
Mon May 8 06:51:35 CEST 2000


Hi,

> We now have a chance to do an Erlang-based pilot project putting load
> balancing and failover ("robustification") in front of a couple remote
> servers running a custom IP protocol over a private WAN.
> I've looked at the white papers on bluetail.com, and am now reviewing
> Eddieware docs, but also wanted to ask the participants of this list:
 
> 1. Other than Bluetail and Eddieware, are there additional
> Erlang-related resources on load balancing we should be consulting?

Not specifically load balancing, but it's worth
brushing up on the options available in Mnesia for building
robust (non single point of failure) distributed databases (etc).

> 2. How usable is Eddieware? There are caveats about the 1.4.0 release
> which came out in February.

Hmm - some people have got it working and are testing/playing with
it. But it's got a couple of serious bugs (which we've fixed). I hope to
do a stable release shortly. I haven't had much time to
work on it recently.

> 3. Is Eddieware still an active project?

Yes :). Just less active than it used to be.

> 4. Are there any recommendations as to how to proceed?

The Eddieware structure should pretty much support what you want
to do; you just need to provide a custom protocol handler
(either in C or Erlang). Check out the inet_server/ module within
Eddieware.

> 5. Where does Erlang give one an advantage on this sort of project?

I guess the big things for us are:

* distributed databases with no single point of failure, Mnesia
  is a great tool!
* really simple RPC
* the gen_server (etc) stuff which is built into the libraries 
  which makes building robust client/server stuff pretty easy (in
  conjunction with the global module for elections when you 
  what a "master" controller of some sort). Also nice "supervisor"
  and "heart" stuff which is essential for robust code.

Geoff




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