Re: 10g AS - what do I need?

OK, a brief intro to Oracle App Server 10g ...

1. App Server comes in 3 'Editions' (for a brief overview of what that means, see http://www.oracle.com/appserver/appserver_family.html)

At the very least, you get an HTTP Server - based on Apache 1.3 (and no, you can't swap it out), and a J2EE App Server called "Oracle Containers for J2EE" (OC4J)historically based on IronFlare's Orion. That is for each installation of AS-10g

B) App Server has a companion that provides repository and security services to all but the simplest OC4J installation. This is called the Infrastructure, and is *prerequisite* if you want high availability, central admin, clustering, and/or identity management (Single Signon, LDAP, etc.).

The Infrastructure formally has 2 parts - App Server Management and Identity Management. Each of these parts needs an Oracle DB instance to house the several repositories required. The DB instance can be the same for each part, but there are dozens of [advanced] reasons to split onto separate machines.

Note that these are NOT - and NEVER should be for a production environment - the instances where your user application data resides.

So IF you need Infrastructure - decisions:

1. Where are the repository instances? (Or allow it to create a new one)
2. Install both Identity Management and App Server Management at the same time? or Install them separately?

	IM can not be moved to another host after install - that generally 
	means a complete install of everything.  

	I recommend separate for flexibility.

3) What machine[s] will support Infrastructure. It's a significant CPU load and should generally be on a separate machine. For flexibility Identity Management, App Server Management (aka Repository) and the repo databases could _each_ be on separate machines.

C) Make sure you have one or more user application database instance (separate from above repository database).

D) Have one or more 'application server machines' ready to go (not the Infrastructure machines). Select appropriate install Edition:

• Java Edition for pure J2EE work. Usually one App Server per host, and that can be AS configured to house several OC4Js. Do this on multiple hosts if you want some form of clustering.

    TERMS:

	Farming means 'using the App Server Mgt Repository for config'
	Cluster means 'Farmed and using one consistent config across several
	  hosts
	Island means 'Clustered and told to sync in-memory persistant state info
	  across App Server cluster'

   Everything past Java Edition *requires* Infrastucture (note 1)

• For Portal Edition and Enterprise Edition, select the specific components that are to go on each host. It is worse than useless to install everything (wasted CPU cycles) if you have multiple hosts. For example, I am a proponent of Web Cache being on a separate host in front of the app servers.

     And ONLY install what you need.  (You need an OHS, OC4J and
     OEM Control for each, but beyond that you chose. Note 1!) App Server
     is very rich in functionality, but each piece of functionality needs
     CPU & memory resources and needs administration.

Note 1: yes, there are exceptions - irrelevant for basic discussion

Hope that helps a bit. Beyond that, ask specific questions

-- 
Hans Forbrich
Oracle training and consulting in Canada
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