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As a long time linux user and developer, I'm glad to see an open
source alternative to the Cisco localdirector and such.
Thanks for all of your hard work.
In any case, I plan to use LVS to provide load balancing and
high-availability for my company.
Our initial setup will be 2 load balancers with 2 real servers. Each
real server will be running a web server as well as a custom
application.
The custom application listens on a socket that every user of our
product connects to. Each user maintains one open TCP connection
throughout the duration of their use of our product. I would say that
the load balancing of our custom application will be much like the load
balancing of say SSH. The average connection time will be much greater
than web traffic... and the total number of connections will be much
greater at any given time.
I am trying to design a system now that will scale to the following
numbers:
Web traffic: Around 500 hits/second
Application traffic: Support up to 20,000 simultaneous connections
It seems to me that the easiest setup is VS-NAT. I can see several
benefits with this setup... namely that the real servers will be
firewalled, and there is no special setup required on them.
However, my concern is whether NAT can support the number of
simultaneous connections I mentioned above. We are planning on using a
Celeron 500 with 128MB of RAM for the load balancing machines.
So, my question to you is - can I use VS-NAT and support the mentioned
number of connections? If I remember correctly, I'll have to increase
some constants when compiling VS to support that number of
connections... but will masquerading be able to handle it? How many
simultaneous connections can one VS-NAT machine possibly handle?
Right now, traffic throughput isn't much of a problem, as we only have a
1Mbit pipe to the internet. However, it was mentioned that this machine
should be able to masquerade at nearly the full 100Mbps speed with the given
processor (and two 100Mbps cards).
My other alternative is to use VS-DR... in which case I would still have
to make sure that VS itself could handle that many simultaneous
connections.
--
Kirk Bauer <kirk@xxxxxxxxxxxxxxx> (404) 964-6071
Chief Technology Officer, TogetherWeb Inc
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