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Help with question on Legacy Connectivity and Common Architecture

 
Subbu Ramarao
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Q.Your existing system has 1 web server,1 app server and DB. if u make them as 3 web servers,3 app servers and DB what is the effect on scalability,availability etc?
2) U have a legacy app....which of these is true to make them accessible by an java application?
a) Wrap j2ee around the legacy app.
b) wrap the legacy app around j2ee
c) have a jsp use java objects and use them to call EJB methods
d) have a jsp use java objects and jsp calls EJB methods
 
Debanjana Dasgupta
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For Q1, Both Scalability and Availability would increase.
For the second one, I would say choice a
Thanks
Debanjana
 
Shankar Ranganathan
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1.The increase in number of webservers and appservers increase in availability.Since availability is related to scalability scalability also increases.
2. a and b
 
Rama Raghavan
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Since availability is related to scalability scalability also increases.

Availability means that if one server goes down you have secondary server to service requests, or else your site (application) will be unavailable.
If you can balance your load across multiple servers, then a more scalable solution can be achieved.
You can provide fail-over or load-balancing or both. But I do NOT see these two related as you put it.
2. a and b

What does "wrap" really mean..? It could mean a lot of things, or nothing at all..How would you conclude this to a and b ?
If anything, I would say c, so the EJB can make calls to legacy application.
Rama
[ February 25, 2003: Message edited by: Rama Raghavan ]
 
Shankar Ranganathan
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Scalability is the ability to support the required quality of service as the load increases.
Availability helps in supporting the required quality of service.
That is why it is related to scalability
Regarding the 2nd qn, it is poorly worded.So there is no point in having a discussion.
SHankar
 
Timber Lee
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Regarding the 2nd question, i think jsp-->javabean-->ejb, so answer is c.
 
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