• Post Reply Bookmark Topic Watch Topic
  • New Topic
programming forums Java Mobile Certification Databases Caching Books Engineering Micro Controllers OS Languages Paradigms IDEs Build Tools Frameworks Application Servers Open Source This Site Careers Other Pie Elite all forums
this forum made possible by our volunteer staff, including ...
Marshals:
  • Campbell Ritchie
  • Jeanne Boyarsky
  • Ron McLeod
  • Paul Clapham
  • Liutauras Vilda
Sheriffs:
  • paul wheaton
  • Rob Spoor
  • Devaka Cooray
Saloon Keepers:
  • Stephan van Hulst
  • Tim Holloway
  • Carey Brown
  • Frits Walraven
  • Tim Moores
Bartenders:
  • Mikalai Zaikin

Load Balancer

 
Ranch Hand
Posts: 154
  • Mark post as helpful
  • send pies
    Number of slices to send:
    Optional 'thank-you' note:
  • Quote
  • Report post to moderator
Hi All,

Thanks in advance.

I would like to know about how load balancer will works, I have couple of queries in it, Could any one please try to help me in finding answers

1) Suppose my first request went server1 and will it be possible to go my subsequent request to different server

2) What are the different load balancing techniqes we have

3) What is clustered environment

4)How can we configure load balancer and clusters in websphere


Regards,
Sree
 
Ranch Hand
Posts: 57
  • Mark post as helpful
  • send pies
    Number of slices to send:
    Optional 'thank-you' note:
  • Quote
  • Report post to moderator
Hi sreedhar
I'll do my best to answer some of your questions in relation to my organisations set up

1) Suppose my first request went server1 and will it be possible to go my subsequent request to different server
Its possible depending on what and how you have set up your load balancer. Some load balancers are just Ip sprayers ,however for web applications that use sessions to store state you probably want a web server such as IBM HTTP Server (IHS) or Microsoft IIS that will route requests to the same server that it originated from and if that server is down route it to another server in the cluster (you'll need to have session replication between servers for the failure scenario).
Websphere has an option to generate a web server plugin file called plugin-cfg.xml file. This file has a list of the servers in your cluster their ports and a server identifier. The server identifier is typcially part of the JSESSION cookie id sent in the request. This plugin-cfg.xml can be installed on the web servers . See Install plugin on IIS
The web servers can then figure out how to direct the request based on the unique server id sent in the JSESSION identifier. If the requests are stateless (like some web service requests) then the web server picks a server based on a routing algorithm.
This excellent tech note explains the algorithm for IIS and IHS Understanding IBM HTTP Server plug-in Load Balancing in a clustered environment

2) What are the different load balancing techniqes we have

See answer 1.
Also if you want a just IP sprayer or network dispatcher then look at documentation on IBMs edge server or f5 load balancer. I have not used F5 but I have heard it mentioned in some infoq architecture presentations.

3) What is clustered environment
This is probably not the correct term but for me a clustered environment typically consists of more than one application server logically grouped together. There are operational efficencies to be had with logically grouping servers such as you can deploy one application across multiple servers and configuring fail (over see answer 1).



 
Ranch Hand
Posts: 446
  • Mark post as helpful
  • send pies
    Number of slices to send:
    Optional 'thank-you' note:
  • Quote
  • Report post to moderator
Brian has already answered your question very nicely. I just wanted to add following.

a. Google IBM Workload Management Application BeenThere to understand the clustering and features available in IHS, WAS ND.

b. You are at least look for a hardward load balancer, which will sit in front of a IHS (IBM HTTP Server), which will sit in front of WAS ND App servers.

c. You can configure session pinning or affinity in both the hardware and the IHS so that all requests go to the same server for a user.

Hope it helps
 
Onion rings are vegetable donuts. Taste this tiny ad:
a bit of art, as a gift, the permaculture playing cards
https://gardener-gift.com
reply
    Bookmark Topic Watch Topic
  • New Topic