3 Replies Latest reply: Nov 24, 2010 2:41 AM by KhaledWLS RSS

    Advantages of WLS clustering

    user602387
      Hi folks,

      I'm trying to identify some of the advantages (or even disadvantages) of clustering at the app tier layer (via weblogic). My situation is that we are deploying Oracle Identity Manager and have included weblogic clustering as part of the design (along with Apache web proxy plugins for HA/Failover). This is a common configuration among J2EE servers in general, but we also have Veritas Clustering available to us.

      WebLogic clustering requires two active servers with load balancing via the web proxy server. Veritias clustering will have one passive server. If the first physical server fails, Veritas will stand up the passive side automatically. Load Balancing can redirect to the other app server once it is up.

      It sounds like they both can achieve the exact same functionality. Is there any additional advantages to app server clustering besides:

      -Load Balancing
      -High Availability/Failover
      -Single deployments to the cluster
      -Less downtime in the event of hardware failure

      Are these statements also true?
      -Centralized management of Key Stores/Certificates
      -Centralized Management of Data Sources

      Does anyone have any other advantages related to application server clustering over using something like Veritas Clustering, or vice versa?
        • 1. Re: Advantages of WLS clustering
          Ravish Mody_MiddlewareMagic
          Hi,

          Weblogic server also provide below things:

          Scalability
          - The capacity of an application deployed on a WebLogic Server cluster can be increased dynamically to meet demand.
          - You can add server instances to a cluster without interruption of service—the application continues to run without impact to clients and end users.

          Backward Compatibility
          - For backward compatibility with previous versions, WebLogic Server also allows you to use multicast for communications between clusters.

          However following APIs and internal services cannot be clustered in WebLogic Server
          -File services including file shares
          -Time services

          Hope this would help you to get a better picture

          Regards,
          Ravish Mody
          http://middlewaremagic.com/weblogic/
          Middleware Magic | Come, Join Us and Experience The Magic…
          • 2. Re: Advantages of WLS clustering
            user602387
            Thanks for the info Ravish, I think for our purposes, we're wondering how it stacks up against Veritas Clustering (VCS), two completely separate technologies that seem to provide the same functionality (from an HA/DR perspective).

            For these two points...

            - The capacity of an application deployed on a WebLogic Server cluster can be increased dynamically to meet demand.
            - You can add server instances to a cluster without interruption of service—the application continues to run without impact to clients and end users.

            It seems that the same thing can be accomplished with a hardware loadbalancer. You could add a server and add it to the hardware loadbalancer rotation.

            The backwards compatibility point is a valid point, but unfortunately, may not be a factor in our evaluation here as there are no older versions of WebLogic available.

            Again, thanks for your input and please let me know if you think of any other functionality that the WebLogic cluster provides above and beyond that of a VCS cluster.

            -AJ
            • 3. Re: Advantages of WLS clustering
              KhaledWLS
              I think the "centralized management" aspect is most important if it is not available in the other clustering method you mentioned.

              I am sure many things are centrally managed via the admin server amobg the cluster such as data sources and application deployment, etc....

              Session replication is also something that must be handled by the WLS cluster, but I don't have real experience with that. I doubt the other clustering method you mentioned handles session state replication.

              Well to be honest the whole clustering features are documented and they are rather extensive:

              http://download.oracle.com/docs/cd/E14571_01/wls.htm