Keith,
I have agree with Matt on some points and disagree on some.
1. You should never have your application server as the webserver. You are
asking for trouble.
2. You can have one server as the main box and another as the backup. We
have sucessfully run that way for over a year. LD does not use ping probe
to see if the box is alive. It use TCP SYN/ACK to determine if the server
is alive. We had appache service die on a server and all the web traffic
moved to another webserver.
3. What sample config are you talking about? Cisco have a lots of Doc on
LD.
Here is a simple diagram of what you want:
WWW1, WWW2, WWW3 in load balance mode connect to APP1 (with APP2 in backup
mode) which is connect to Database1.
You can increase the application servers if you are using "sticky" command.
Your database will be safe if it support transaction rollback. That is what
will happens when your app server dies.
I hope this is of help.
Albert
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]
Sent: Friday, February 09, 2001 12:58 PM
To: [EMAIL PROTECTED]; [EMAIL PROTECTED]
Subject: RE: Local Director Config
See below
-----Original Message-----
From: Keith Whitfield [mailto:[EMAIL PROTECTED]]
Sent: Thursday, February 08, 2001 5:33 PM
To: [EMAIL PROTECTED]
Subject: Local Director Config
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?
You'll need to be running co-standby or another clustering software to
replicate the data. Local director won't do this for you. A common
architecture is to avoid having that data saved directly to a web box,
rather to separated and secure data stores which centralizes backup,
administration ... yadda yaddda
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?
The short answer to this question is no. The way local director determines
that a server is down is by using ping probe. If you're running www services
or smtp services and those services fail yet the machine remains working, no
fail over will occur. My belief, although it may be contrary to other's
beliefs, is that local director is good only for load distribution and not
fail over, though it makes the process of recovery easier if you're using
the LD LUD.
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?
I may not have a clear idea of what you mean by this. Clustering in the
logical sense or the physical sense? I have always configured local
director only after physically connecting and configuring those load
balanced servers.
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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