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Re: GSLB global server loadbalancing - possible?

* Mario Kleinsasser <mario.kleinsasser+debian@gmail.com> schrieb:

> At work we have an Apache loadbalancer (mod_jk, reverse proxy, for intranet)
> which is encountering about 54 million requests from all over Europe. We've
> also some branches in North America and Southeast Asia. This is a huge
> corporate network an I would like to implement some kind of global server
> loadbalancing so that clients could connect (to the domain) even when the
> main data center isn't responsible.

Load balancing and desaster failover are completely different issues.

If your corporate system is quite big, I'd probably advise BGP-based
failover (take care of properly resetting tcp sessions, etc) to a full
mirror datacenter - that's eg. what one of my customers (a major German
ISP and mass-hoster) does. For geographical load balancing you could use
multisite announcements (like eg. akamai does), but that needs proper
support by the whole systems architecture (multimaster synchronization
over hi latency links, etc).

> So before we will purchase a commercial solution (F5, Netscaler, foo, ....)
> I would like to ask how you would build up such a configuration based upon
> open source?

It's not a matter of invidual products, but the systems architecture.
We'll need to know *much* more about it before we could give any advise.

> I guess it will be a combination of Bind (availability for views to connect
> the source IP to different DNS resolutions), Linux-HA and maybe a self
> written script(?) based logic to manipulate the components.

Might be good tools for that. But can't tell without more information.

> Anyone who have already implemented a similar solution? Any advice for
> know programs?

Yes, indeed. For example, mirroring cluster node's storage space via
DRBD (beware: synchronous write performance over the ocean is *really*
bad. the commercial proxy, essentially a buffered pipeline, helps a bit,
but still suboptimal) - we already have some concepts for a transaction-
based replicated blockstore (which also includes cheap snapshots, etc),
but not yet the resources to actually implement it.

 Enrico Weigelt, metux IT service -- http://www.metux.de/

 phone:  +49 36207 519931  email: weigelt@metux.de
 mobile: +49 151 27565287  icq:   210169427         skype: nekrad666
 Embedded-Linux / Portierung / Opensource-QM / Verteilte Systeme

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