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What is a Cluster

Rahul Mahindrakar
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Joined: Jul 28, 2000
Posts: 1859
Hi,
I am looking out for a definition of a Cluster. Any links or documents will help. Also how is clustering and Work Load Management different.


[This message has been edited by Rahul Mahindrakar (edited May 16, 2001).]
daman sidhu
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Joined: Aug 19, 2000
Posts: 184
hi Rahul,
There was a very good article on clustering in javaworld.com some time back, i will see if i can find its url and paste it over here.
daman sidhu
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Joined: Aug 19, 2000
Posts: 184
but just for the definition we make clusters of ejb containers which are replicas which handle the workload, and the policy to be used in them is that we need to have a mirror server of the server which is handling requests and if the main server fails over then the second one takes on, and immidiately a 3rd server is made the mirror server of the second one so the integrity is maintained, besides workload.
Regards,
Daman
Rahul Mahindrakar
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Joined: Jul 28, 2000
Posts: 1859
Can we say that a cluster is a Application Server with a single Administrative repostitory.
daman sidhu
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Joined: Aug 19, 2000
Posts: 184
here is the link , check this out all will be clear,
http://javaworld.com/javaworld/jw-02-2001/jw-0223-extremescale_p.html.
Rahul Mahindrakar
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Joined: Jul 28, 2000
Posts: 1859
daman,
Thanks for the article. Looks great and i have started reading it. But only thing i do not like is there is no mention of WAS here

In this article, Abraham Kang introduces J2EE clustering, shows how to implement clusters, and examines how
Bluestone Total-e-server,
Sybase Enterprise Application Server,
SilverStream Application Server, and
WebLogic Application Server
daman sidhu
Ranch Hand

Joined: Aug 19, 2000
Posts: 184
Hi Rahul,
Yes the article is good but is not specific to was , but leaving out the was implementation part, we make clusters in was by making a clone of application server and selecting a node on which to make the clone , thus we can make the clone of the application on a same pc as well select one node on the network and make a clone there.
Regards,
Daman
Rahul Mahindrakar
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Joined: Jul 28, 2000
Posts: 1859
daman,
We can create clones on other machines only if we have the node listed on my machine. Is it true that the other machine will be listed as a node only if the two application servers share the same administrative repository.
daman sidhu
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Joined: Aug 19, 2000
Posts: 184
Rahul,
This I myself havenot checked out, if u get some info regarding this then do let me know too.
Nanjangud Nanjundaiah
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Joined: May 15, 2001
Posts: 186
The WAS 3.5 Adv for iSeries has a section on Session Clustering, under Sessions. That might give you some information.

------------------
The Rancher Formerly Known As Nanhesru Ningyake.


The Rancher Formerly Known As Nanhesru Ningyake.
daman sidhu
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Joined: Aug 19, 2000
Posts: 184
Rahul,
I found a rebook specifically on clustering in websphere on the redbooks site, go there and check it out,i havent gone through in detail but i understand that the admin repository will have to be the same for all the servers.Hope that might solve your queries.
Cheers,
Daman
daman sidhu
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Joined: Aug 19, 2000
Posts: 184
Rahul,
I found a rebook specifically on clustering in websphere on the redbooks site, go there and check it out,i havent gone through in detail but i understand that the admin repository will have to be the same for all the servers.Hope that might solve your queries.
Cheers,
Daman
Rahul Mahindrakar
Ranch Hand

Joined: Jul 28, 2000
Posts: 1859
Thanks daman,
Actually i am working on the same pdf that you mentioned. Its this book
sg246153 WML,Clustering, Scalability
I am trying to understand
How to split the administrative repository from the Application server
This i have acheived sucessfully with db2 and Oracle. though oracle still gives me some problems the problem will be sorted out soon.
How to have the HTTP server on a different machine, the application server on another and the backend on another.
This i have been able to undertake to some extent. I am working on it intensely and lets see what are the results.
By the way did you know i am in pune??
Bye
daman sidhu
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Joined: Aug 19, 2000
Posts: 184
Hi Rahul,
That is an interesting area to explore and i am looking forward to your outputs on clustering since i havent really tried itpractically besides makinga model and clone on the same pc.YEs i know that u are working for Zensar in pune which is level 5 company right? I am working in bombay in PCS, maybe we can do some talking on the phone and it is local only.Looking forward to your inputs.
Daman
daman sidhu
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Joined: Aug 19, 2000
Posts: 184
One more thing, did u find out whether it is possible to have seperate admin repositories for the clones? And have u worked with team environment in VAjava with central repository? If so caould u tell me how to configure the Repository server and the software for that.
Daman
Rahul Mahindrakar
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Joined: Jul 28, 2000
Posts: 1859
daman,
Sure we can help each other out in this. Any how i have just now created a cluster. I have application servers with the same administrative repository on an oracle rdbms. When i started out it seems an impossible dream. But it feel great now to have completed it. I am even able to have my administrative repository on a DB2 system. I now plan to bind these two application servers with a single HTTP server running on another machine. Actually few of my friends are on leave and i am using their machines for my "demo project"

One more thing, did u find out whether it is possible to have seperate admin repositories for the clones?

i do not have much knowledge in this regard, but i feel that for a cluster you need to have a single admin repository at least in WAS.

And have u worked with team environment in VAjava with central repository?

I don't plan to work on VAJ for sometime till end of next month., till then i plan to complete a lot of work on WAS.
daman sidhu
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Joined: Aug 19, 2000
Posts: 184
Rahul,
What setting do we have to do for keeping the HttpServer on a seperate pc? And the same for keeping the DB on seperate PC from WAS?
Regards,
Daman
daman sidhu
Ranch Hand

Joined: Aug 19, 2000
Posts: 184
Hi Guys,
I worked out how to manage team server ie working in team environment in Vajava, if interested then ill paste some info here.
Daman
Suneel Setlur
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Joined: Nov 26, 2000
Posts: 202
Hi
Could you please post the link to the pdf on clustering?
Daman:
Have you been able to separate HTTP Server to a different PC?
If yes, please give the steps ....
Suneel

Suneel
daman sidhu
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Joined: Aug 19, 2000
Posts: 184
Suneel,
Rahul has managed to seperate HttpServer on a different PC from WAS, please do post information regarding that here.What i was talking about in the last post was working in team environment with Visual Age for Java in which we have a central repository and all the team members work on the same repository, for that we need to install one more server called EMSRV on the central repository PC.It is a good experience working in team env, and we are planning to use it for the next project.
Hope rahul pastes the http server related info here.
Regards,
Daman
Rahul Mahindrakar
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Joined: Jul 28, 2000
Posts: 1859
daman and suneel,
I am following the pdf provided by IBM here . Based on this i have used OSE remote to separate the HTTP Server and the Application Server. This impoves the Horizontal Scalability in my system.
Basically i have installed HTTP Server with the plugin on one system and the Application server on the other. I have changed some properties of the queues.properties, vhosts.properties and rules.properties which are available in the temp folder of websphere and copied them to the machine on which the HTTP server is located.
It works fine. If you want to test it out and have any problems do get back to me
 
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subject: What is a Cluster