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Hi
On Fri, 2006-08-04 at 17:51 -0700, Ricardo Kleemann wrote:
<snip>
> So I thought, if it were possible to run an instance of LVS on BOTH the A/B
> servers, and just use it for load-balancing the 2 db servers (which are
> setup with multi-master replication), then I would not have a single point
> of failure. Basically 2 redundant DB servers, and 2 redundant app servers.
>
> Just wondering if that would work...
Short answer: yes :)
You will need to solve a few minor problems, as you'll end up with a
system with a pair of VIP addresses for your clients to connect to.
That means you'll need to do something like DNS round-robin; in turn
that means you'll need to endure the outage if (for example) one of
your servers has to be taken (or goes) offline and stops responding.
Alternatively you'll need something to manage both the LVS and HA
aspects of the system, like keepalived or heartbeat.
You will also need to solve the potential problem of both servers being
configured to handle both VIPs as both LVS director and realserver -
this one can tie you in knots very easily. I usually manage it with
fwmarks on the input interface (the one facing the clients).
Give it a try and see how you get on. All you're doing is moving the
director functionality back onto your realservers, and this is most
definitely possible.
Graeme
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