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> > also, as side question about how LVS handles a single client that uses
> > multiple proxies... for instance aol, when an aol user attempts to connect
> > to a website, each request can come from a different proxy so, how/if does
> > LVS know that the request is from the same client and bind them to the same
> > server?
>
> if this is what aol does then each request will be independant and will
> not neccessarily go to the same realserver. Previous discussions about aol
> have assumed that everyone from aol was coming out of the same IP.
> Currently this is handled by making the connection persistant and all
> connections from aol will go to one realserver.
If ISP user (eg AOL) has a proxy array/farm then the requests are _likely_
to come from two possibilities:
* A single subnet (if using an L4/L7 switch that rewrites ether frames,
or using several NAT based L4/L7 switches)
or
* A single IP (If using the common form of L4/L7 switch)
The former can be handled using a subnet mask in the persistance settings,
the latter is handled by normal persistance.
*However* In the case of our proxy farm neither of these would work
since we have 2 subnet ranges for our systems - 194.83.240/24 &
194.82.103/24, and an end user request may come out of each subnet totally
defeating the persistance idea... (in fact dependent on our clients
configuration of their caches, the request could appear to come from the
above two subnets or the above 2 subnets and about 1000 other ones as
well)
Unfortunately this problem is more common that might be obvious, due to
the NLANR hierarchy, so whilst persistance on IP/subnet solves a large
number of problems, it can't solve all of them.
Michael.
--
National & Local Web Cache Support R: G117
Manchester Computing T: 0161 275 7195
University of Manchester F: 0161 275 6040
Manchester UK M13 9PL M: Michael.Sparks@xxxxxxxxxxxxxxx
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