great post!
----- Original Message -----
From: "Moe Tavakoli" <[EMAIL PROTECTED]>
To: "Keith Whitfield" <[EMAIL PROTECTED]>; <[EMAIL PROTECTED]>
Cc: <[EMAIL PROTECTED]>
Sent: Friday, February 09, 2001 1:10 AM
Subject: Re: Local Director Config
> You have the basic idea. the Local Director
> load-balances per packet. Now you are talking about 2
> servers behind the LD and you want the same user
> (session) to continue to go to the same server till
> the transaction is complete (usually do to the fact
> that the server keeps the session ID and tracks it,
> very common.) What you will need to use is the STICKY
> command. This command will allow you to send a
> certain client session to the same "real" server.
> So once you create your 1 virtual server and 2 real
> servers type in the sticky command and apply it to the
> Virtual address. There are foure ways that the box
> will do the sticky:
>
> IP: Based on source and destination of the request.
> The problem here would be in the case your users are
> coming from a PAT. Lets say you have one large user
> base coming in with the same source. The LD would
> send these requests from that IP to one real (thinking
> it's the same session.) This could get in the way of
> actual load balancing. But th egood thing is that it
> works and is very easy to configure and make sure it
> works.
>
> SSL: This is the other sticky type which has been
> supported since aleast ver. 4.4. This tracks the SSL
> session ID and makes sure the client with the same SSL
> Session ID keeps going back to the same server. This
> had some problems with a couple of IE4.? vers, where
> the browser would request a new SSL ID too soon (the
> SSL TTL on the browser was set to small.)
>
> App Cookie: This was introduced in the 5.? releases.
> This allows you to define a session based on the
> cookie yor app gives to the session. This is assuming
> that you use Cookies. If your using cookies this is a
> pretty solid solution, though it is a bit slower than
> the previous two.
>
> LD Cookie: Released along witht the previous. You
> also have the option of having the LD assign cookies
> to the traffic (a great option when your app doesn't)
> Again this is a bit slower than the first two.
>
>
> On the cluster issue, remember that the cluster has a
> single VIP and this is the way it should be accessed.
> It will do it's own load-balancing (hopefully.) So the
> LD would be useless in this case, unless you have two
> sets of clusters that you'd like to load-balance.
>
> When installing also look at the way the LD is doing
> it's load-balancing. By default it is set to
> least-conn. That means the unit with the least amount
> of open connections gets the request. This may or may
> not be the right one for you, so read into them and
> apply it to your scenerio.
>
> Remember that your install is a very basic one:
> You need to set the management IP
> Set the Virt
> Set the Real
> Bind them
> Set your sticky
> The Default Gateway
> and plug two interfaces to separate VLANS.
> (I think thats it!)
>
> Also remember that the LD is a bridge (and never
> bridge it) the servers behind it use the same address
> space as the network in-front of it and use the
> default gateway of the network in-front of the LD.
>
> I hope that helps, I'm sure I would spew out some more
> if my fingers weren't tired!
>
> Moe Tavakoli
>
> --- Keith Whitfield <[EMAIL PROTECTED]> wrote:
> > Thanks for the response. So, In what kind of server
> > setup does
> > LD work? Is there a way to disable load-balancing on
> > the LD and
> > configure it to work as a Redirector?
> >
> > I don't know if I am asking for something that LD
> > doesn't do.
> > But, I am confused at the scenario when LD is
> > implemented and
> > what are the things I need to keep in mind at the
> > server sides
> > when I go ahead with LD solution.
> >
> > Thanks
> >
> > <[EMAIL PROTECTED]> wrote...
> >
> > I'm not even sure it is possible to load balance
> > between two
> > servers in a cluster. Since clusters are generally
> > presented as
> > one server.
> >
> > Clayton
> > "Keith Whitfield" <[EMAIL PROTECTED]> wrote
> > in message
> >
> [EMAIL PROTECTED]">news:[EMAIL PROTECTED]...
> > Hi...
> >
> > I am in the process of implementing a Local Director
> > for the
> > servers in our company. Right now in the process of
> > documenting
> > the requirements and design of it. I have some
> > questions for
> > which the cisco site don't have information in the
> > LD
> > documentation. I have 2 servers on which I need to
> > do load
> > balancing as well as have a fail over redundancy in
> > case one of
> > them goes down. I can achieve this by the LD. But
> > the traffic
> > that goes via the LD are real time transactions and
> > I don't know
> > how the application(our) will respond to these
> > requests, since
> > LD laod balances on a packet-packet basis. Basically
> > we will be
> > having 2 instances of the application running.So, my
> > questions
> > are
> >
> > 1.To achieve synchronization between the servers for
> > every
> > transaction that occur Do I need to have a
> > clustering software
> > for these servers?
> >
> > 2.Can I configure the LD to forward all requests to
> > only one
> > server (even though it is connected to another
> > server) and make
> > the second available when the first goes down?
> >
> > 3. Does the The sample configs in the LD
> > documentation assume
> > that the servers are already clustered or have only
> > static data
> > for the outside users?
> >
> > Any comments on this or if someone has a similar
> > setup what I am
> > trying to acheive , please reply back.
> >
> > Thanks in advance.
> >
> > Regards
> > Keith.
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