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"Doug Schasteen" <dschast@xxxxxxxxxxxx> writes:
> Ok. I'm not sure exactly how to respond to this, but I'll try. Pretty
> much any web server running new applications will "require" persistence.
> I'm actually not a unix admin by trade, I'm a php programmer, so this is
> one area where I actually know what I'm talking about. Not everything on
> a web site uses server side sessions, but some things do. Some things
<snip>
> deal since it just means that everyone from that NAT'd office will go to
> one webserver until they are all done and next time it switches them to
> the other server. It will still be load balancing but just not as
<snip>
> their session and hitting a different server each time. Anyway, I should
> be ok when using server-side sessions + LVS persistence. I think.
Two points on this.
Firstly, there are plenty of ways to solve the sessions problem
without persistence: database your sessions, use a shared file store,
keep all the useful info in a cookie (if its small enough)
etc. etc. Some are more costly than others, and may affect
scalability. They must be considered carefully, as we are doing at the
moment
Secondly, watch out for IP based persistence... you may find to
_whole_ of AOL (if you're aiming at that market ;-) hitting just one
of your servers, and ignoring the rest! Its not just small offices
that use NAT. As well as AOL, one of the biggest UK ISPs (Freeserve)
forces all web traffic through proxy servers, and they're not alone in
doing this.
Chris
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