--On Friday, October 13, 2006 8:39 AM +0200 Giovanni Baruzzi
<[EMAIL PROTECTED]> wrote:
Hi,
Yes, I relate to HW-based load balancers.
I wonder why you don't have these issues? Which kind of software are you
employing?
Is support for long-lived connections given?
As you understand, these issues are not hardware of software related, they
are much more related to the design.
What lbnamed/lbcd do, are simply return the best available server to the
querying client, based off of weights.
For example, there is a client, and it wants to connect to
"ldap.stanford.edu". Well, if we look at ldap.stanford.edu using the
"host" command, we see:
host -t txt ldap
ldap.stanford.edu is an alias for ldap.best.stanford.edu.
ldap.best.stanford.edu text " 450/1.000 ldap3.stanford.edu"
ldap.best.stanford.edu text " 450/1.000 ldap1.stanford.edu"
ldap.best.stanford.edu text " 450/1.000 ldap4.stanford.edu"
ldap.best.stanford.edu text " 480/1.000 ldap2.stanford.edu"
which means that ldap1, ldap3, and ldap4 all have the same lowest weight,
so any of them is equally likely to be returned.
tribes:~> nslookup ldap
Server: cassandra.Stanford.EDU
Address: 171.64.7.77
Name: ldap1.Stanford.EDU
Address: 171.67.22.57
Aliases: ldap.Stanford.EDU, ldap.best.Stanford.EDU
so any client requesting to talk to "ldap.stanford.edu" will talk to
"ldap1.stanford.edu". Since there is actually no software involved
*between* the connection, the client simply connects straight through to
the server, meaning that there is nothing to interfere with long-lived
connections.
What lbnamed/lbcd does not do, is support sticky sessions needed by some
services, mostly web based. But for everything we have that does not
require sticky sessions, we use lbnamed/lbcd.
Other examples:
Web: www.stanford.edu
Web: cgi.stanford.edu
Web: webmail.stanford.edu
Web: proxy-service.stanford.edu
Mail: smtp.stanford.edu
Whois: whois.stanford.edu
Shibboleth: idp.stanford.edu
etc.
--Quanah
--
Quanah Gibson-Mount
Principal Software Developer
ITS/Shared Application Services
Stanford University
GnuPG Public Key: http://www.stanford.edu/~quanah/pgp.html
---
You are currently subscribed to [email protected] as: [EMAIL PROTECTED]
To unsubscribe send email to [EMAIL PROTECTED] with the word UNSUBSCRIBE as the
SUBJECT of the message.
