Deployment architecture 7.00 J2EE WAS

[former_member191469]

I was looking for some information on how deployments (J2EE apps, SCAs, anything through SDM, JSDM) work on the 7.00 J2EE stack. How do the files get copied to the different file systems in a clustered environment? How does it work if users are using the application that is being updated? Should hot-deployments be done or should they be deployed when the system is quiet? Is any of this documented anywhere?

[former_member191469 · Accepted solution]

Dagfinn, thank you for your reply. It was very helpful. I would like to leave the question open in case other people have additional information. Have you had any experience with hot deployments causing problems with the J2EE engine in general so that other applications had problems?

Edited by: Timothy Rockhill on Apr 8, 2008 12:44 PM

[Former Member · Accepted solution]

Hi,

No problems leaving the question open, I'll even bump it to the front of the queue

We've had some minor caching problems in portal applications. Therefore (and because of company policies) we've done the deployment at offhours in order to allow us a restart of the system if necessary.

Dagfinn

[Former Member]

Hi,

>How do the files get copied to the different file systems in a clustered environment?

I believe the server node SDM connects to is categorized as the master node.

When it has deployed the application in the database and on its own server node, it through the message server triggers a cluster synchronization of the application.

So the files are sent through the message server (or directly between master node and the others as the message server allows this if there is a lot of data)

>How does it work if users are using the application that is being updated?

Good question. I believe the SAP system does the following:

1. Stop the application, throwing out all users and possibly removing any session data

2. Update the application (user will get error message that application is not available if trying to access)

3. Start the application (once up users will be able to access it)

To find out more, put on ALL logging in the log configurator services in visual admin for the location com.sap.engine.services.deploy (and possibly com.sap.engine.core.cluster)

>Should hot-deployments be done or should they be deployed when the system is quiet?

Depends on the business criticality of the application. I would normally recommend off-hours for the deployment, but as far as I knowSAP supports deployment during high load as well.

>Is any of this documented anywhere?

Not that I know of.

The information above is based on analysis of some cluster synchronization problems for WD for java application we had on earlier versions.

Cheers

Dagfinn