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At 12:30 PM 9/13/2002, you wrote:
Aurélien DEHAY wrote:
> > > The problem is that the 8 reals servers doesn't support virtual hosting
>
> > what is "virtual hosting"?
> One IP, multiple domains. Like Apache does. Ok, it's maybe not cleat en
the sentence. Apologies.
OK so the realservers don't support name based httpd? If they work that
way now, then when you put them behind an LVS director, they should
work also.
If you have 3 IPs then I assume you have 3 websites?
I suspect an error in the Apache config file. The Virtual Hosting stuff is
a little confusing and Apache is pretty picky about it. In Apache
(httpd.conf) make sure the IP that LVS is redirecting to is defined in the
Virtual Hosting params. If your are depending on the request to come to a
specific IP address to differentiate between web sites then you will need
all three IPs in LVS redirecting each of the 3 IPs to 3 unique IPs for each
web server.
When you add in the persistence problem I suspect you're doing something
that's a bad idea. I suspect the reason you need persistence (or think you
do) is because you're storing state or session information locally on each
web server. Although it may work, it's a weak design for a web app. If
you want a high performance solution, use a common server with something
like MySQL on it to hold the session or state information. If you're
nervous about the single point of failure on the database box, add a
replicated sever behind it. Keeping state info on each web server is just
a weak solution in a highly-available high-performance
environment. Hardware is pretty cheap in comparison.
I would suggest 2 LVS servers running HA between them, 2 or more web
servers, and 2 session/state db servers running replicated. Bang for the
buck, it's a good solution and gives you a pretty resilient, robust, and
scalable system. The system you are trying to implement now will hammer
33% of your user sessions if you have a web server failure and ALL of them
if you have an LVS server failure. With the proper monitoring and HA, no
single machine failure will hammer your users in the system I suggest. For
the price of 6 or 7 Linux servers boxes, you have what people used to pay
more than $100K for just a few years ago.
That's my two cents worth.
--
Bobby Johns
bobbyj@xxxxxxxxxxx
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