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>>>>> On Sat, 15 Jul 2000 17:19:24 -0700, Horms <horms@xxxxxxxxxxxx> said:
> What you describe is layer 7 switching - in this case switching
> at the HTTP protocol layer. The LVS kernel patches do layer 4
> switching - that is swiching at the IP protocol layer.
> Wensong was working on some code a while back to do layer
> 7 switching but I don't think any progress has been made on this
> recently. Certainly it is code that needs to be written as
> there seems to be a fair amount of interest in layer 7 switching.
I have already said it the last time it came up: I guess the code you
mean is just a combination of LVS with squid boxes. Squid does all you
need with all the intricacies of the HTTP protocol addressed (and if
you want ICP) and it has many years of experience. In squid
terminology this is called a redirector
(http://www.squid-cache.org/Doc/FAQ/FAQ-15.html) for its role as a
director and an accelerator
(http://www.squid-cache.org/Doc/FAQ/FAQ-20.html) for its role as a
buffer and cache.
I'd choose this topology:
LVSdirector
squid1 squid2
webserver1 webserver2 webserver3 webserver4 webserver5
Note that a squid and a webserver can coexist in a single box. Note
also that squids can cache webservers' output and thus reduce the work
for them. And finally note that several squids can exchange digest
information about cached data if they want.
Strictly speaking, a single squid can take the role of an LVSdirector,
but only for HTTP. It's slower, but it works. I find the above
topology should be encouraged. We're going to build such a toy
ourselves and will report about success or failure in a few months.
--
andreas
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