Highly Available WAS 6.40

[Former Member]

Hi,

I am looking at building EP6 SP4 when it arrives, on WAS 6.40 to provide a highly available solution for portals.

I'm sure I have seen somewhere on SMP that the tricky single point of failure in WAS are the message server and enque server in central services. I assume this to mean that in order to protect a stateful J2EE app (EP6) I dont need to be that concerned about failure of a central instance - other than the ENQ and MS services.

The EP6/NW04 dox talk a lot about protecting the ENQ and MS, but I have yet to (re)discover relevant configuration dox on how to actually implement a highly available ENQ and MS.

Could anyone point me in the right (Service Market Place?) direction?

Thanks.

[Former Member]

Hi Stuart,

yes, you are right - the message and enqueue servers are SPOF in a Web AS cluster. Add the DB to that. So, the real HA cluster can be achieved using Switchover software (protects your cluster also against host machine failure, network adapter failure, etc.)

The docs you are looking for are located here: http://service.sap.com/ha -> Media Library -> Documentation -> HA Documentation and Switchover. In BC SAP High Availability 6.40 document under HA DOcumentation you can find general considerations about using switchover (how it works in general, how it protects your cluster, etc.)

Under Switchover you can find the SAP Web AS in Switchover Environments (6.30) document that discuss in more detail what you need to do to setup the HA cluster.

However, protecting the central services and the DB means that your cluster will stay operational and in sync. This does not provide state preservation of stateful applications. If you need to preserve any state for your J2EE applications, consider using failover. For more info, see those pages in the documentation:

http://help.sap.com/saphelp_nw04/helpdata/en/8f/d6e45953a494499ea1b79ab16321d2/frameset.htm

http://help.sap.com/saphelp_nw04/helpdata/en/90/044cc585eaba42b649f161818b0fdf/frameset.htm

Hope that helps.