6 Replies Latest reply: Mar 5, 2014 6:31 PM by JayaPrakash -Oracle RSS

High Availability in OracleAS

Jimbo Explorer
Currently Being Moderated


Hi, I am trying to understand what underpins the Clustering in OracleAS.

 

I know that for Databases you can use RAC and Oracle Grid Infrastructure ( formerly Oracle Clusterware )

I know for general server clustering of applications you can use Oracle Grid Infrastructure or 3rd party / server vendor clustering.

 

Q1. However OracleAS seems to have its own clustering solution, is that correct ( there appears to be a separate HA manual for it )

 

Q2. OracleAS clustering can create OracleAS instances on the same physical server or separate physical servers ? Why would you have the instances on the same server - it means the server / processor is the same single point of failure i.e. if it crashes you lose all your OracleAS instances !

 

Q3. If you have OracleAS clustered over different servers, do you need to have some sort of 3rd party server clustering in place for OracleAS to sit on top of ?

 

Q4. The HA guide for OracleAS talks about OracleAS Middle Tier vrs OracleAS Infrastructure Tier. What components appear in each of these tiers. My understanding of OracleAS is that it is comprised of -

i. J2EE/OC4J Server

ii. Oracle Portals

iii. Oracle Identity Management ( comprising of Http Server, SSO & OID )

iv. OracleAS Guard ( embedding of some of the Data Guard technology ? )

v. BI Discoverer

vi. Forms Server

vii. Reports Server

 

Q5. Oracle Application Server at 10gR3 ( 10.1.3.5 ) appears to be the last deployment of OracleAS. After this although still called Oracle Application Server, it appears to change to Web Logic Server - is that correct ?

 

Q6. Does Web Logic Server have a different Clustering solution again from OracleAS ?

 

Please advise,

Jim

  • 1. Re: High Availability in OracleAS
    JayaPrakash -Oracle Pro
    Currently Being Moderated

    Hi ,

     

    Q1. However OracleAS seems to have its own clustering solution, is that correct ( there appears to be a separate HA manual for it )

     

     

        Yes it has it own Clustering solution. For more information on HA please go through the below documentation :-

     

      http://docs.oracle.com/cd/B14099_19/core.1012/b14003/toc.htm

     

    Q2. OracleAS clustering can create OracleAS instances on the same physical server or separate physical servers ? Why would you have the instances on the same server - it means the server /

        processor is the same single point of failure i.e. if it crashes you lose all your OracleAS instances !

     

     

        Yes OracleAs Instances could be created under same server or across machines

      

      If you have created  the OracleAS instances on the same server which is called vertical clustering and in-case of a failures of the server the whole OracleAs would be down and there cannot be any request flow.

     

      If you have created the OracleAS instances on the across servers which is Horizontal clustering and in-case of a failures of the one server the request would be served because the Oralce As Instances are across the machines and which  would be proper HA.

     

     

    Q3. If you have OracleAS clustered over different servers, do you need to have some sort of 3rd party server clustering in place for OracleAS to sit on top of ?

     

     

        In-case if OralceAs clusters over different servers there is no need to have any third party server clustering in place.

     

     

    Q4. The HA guide for OracleAS talks about OracleAS Middle Tier vrs OracleAS Infrastructure Tier. What components appear in each of these tiers. My understanding of OracleAS is that it is comprised of -

    i. J2EE/OC4J Server

    ii. Oracle Portals

    iii. Oracle Identity Management ( comprising of Http Server, SSO & OID )

    iv. OracleAS Guard ( embedding of some of the Data Guard technology ? )

    v. BI Discoverer

    vi. Forms Server

    vii. Reports Server

     

     

         As per OracleHA guide the below would be part of Mid-Tier :-

      

         i. J2EE/OC4J Server

         ii. Oracle Portals

         v. BI Discoverer

         vi. Forms Server

         vii. Reports Server

      

      As per OracleHA guide the below would be part of Infra-Tier :-

      

         iii. Oracle Identity Management ( comprising of Http Server, SSO & OID )

         iv. OracleAS Guard ( embedding of some of the Data Guard technology ? )

     

    Q5. Oracle Application Server at 10gR3 ( 10.1.3.5 ) appears to be the last deployment of OracleAS. After this although still called Oracle Application Server, it appears to change to Web

        Logic Server - is that correct ?

     

      Oracle Application Server at 10gR3 ( 10.1.3.5 ) appears to be the last deployment of OracleAS which has [ J2EE/OC4J Server and SOA/BPEL] and is still called as Oracle Application Server

      because it has OC4J components in it.

      

      Yes in new version of Fusion Middleware OC4J has been replaced by Weblogic.

     

    Q6. Does Web Logic Server have a different Clustering solution again from OracleAS ?

     

     

     

         Yes clustering differs in Weblogic when compared with OracleAS.

     

     

    Please let us know more clarification is required.

     

    Regards,

    Prakash

  • 2. Re: High Availability in OracleAS
    Jimbo Explorer
    Currently Being Moderated

    I guess one of the things that is confusing me is why OracleAS has a different clustering solution from Oracle Clusterware.

     

    My understanding is that Oracle Clusterware effectively clusters servers or more precisely the oracle or non oracle applications running on those servers ( though for Oracle Databases, Oracle RAC is specifically used to cluster the database instance )

     

    Since OracleAS is an Oracle application - then why does it not simply use Oracle Clusterware to achieve clustering like any other oracle or non oracle application ?

     

    Does the clustering solution for OracleAS simply reside in the base code/binaries of OracleAS itself ?

     

    thanks,

    Jim

  • 3. Re: High Availability in OracleAS
    JayaPrakash -Oracle Pro
    Currently Being Moderated

    Hi,

     

    Q1. Yes I appreciate that vertical clustering does not give HA i.e. failover or load balancing. That is the point of my question. If Vertical Clustering does not give HA then what is the point of it at all ? Why use Vertical Clustering at all - what's its purpose ?

     

     

     

           Vertical clustering, sometimes referred to as scaling up, is adding Oracle Application Server instances to the same machine.

           Vertical scaling is useful for taking advantage of unused resources in large servers.

           You can use vertical clustering to create multiple JVM processes that, together, can use all of the available processing power.

     

     

     

    Q2. You say Oracle Clusterware is used to cluster an operating system. My understanding is that through Oracle Clusterware you can effectively cluster any oracle or non oracle application

           ( though for Oracle Databases you specifically use RAC to cluster the database instance )? Is that correct ?

     

     

     

     

            Yes RAC is used to cluster database instance.

     

            Clusterware is a product of Oracle for enabling clustering and here are multiple ways  for clustering  and it depends on the way you choose

     

     

     

    Q3. Does the clustering solution / capability of OracleAS therefore simply reside in the base code / binaries of OracleAS ?

     

     

          It resides in the base code.

     

    Regards,

    Prakash.

  • 4. Re: High Availability in OracleAS
    Jimbo Explorer
    Currently Being Moderated

    Thanks Prakash,

     

    I guess I conceptually have a problem with that definition of vertical scaling. My understanding had always been that vertical scaling was adding more processing resource to your server. Horizontal scaling was adding more servers !

     

    I don't see how adding additional JVMs on the same server will use up any more spare resource than a single JVM could use ( unless a single JVM has a cap on the resources it can use i.e. the number of processes it can cope with ). For example I see no difference between a single JVM running 100 processes and 2 JVMs on the same server running 50 processes each ( in fact you could argue that the overhead for a second JVM uses up more resources that the single JVM running 100 processes ). A JVM should be able to continue to create/service processes until the resources of the server are reached.

     

    In rergards to the Clustering Solution for OracleAS, I am just confused as to why Oracle have effectively used a different method / solution when they had Oracle Clusterware available i.e. why didn't they simply use Oracle Clusterware to cluster OracleAS, rather than having OracleAS use its own in-built solution ? I think the same situation exists with Web Logic Server i.e. it uses its own clustering solution ( different again from the OracleAS one ) rather than using Oracle Clusterware. You would have thought Oracle would have consildated everything to use Oracle Clusterware !

     

    Jim

     


  • 5. Re: High Availability in OracleAS
    JayaPrakash -Oracle Pro
    Currently Being Moderated

    Hi Jim,

     

     

    Adding additional JVM's on a single machine would cause issues as at some point of time all the resources might have been used by the JVM's which were already running and

     

     

    there would be any resource for the next JVM to use the resource on the OS to execute the query it has to.

     

     

     

    Regarding the Clustering solution for OracleAS inorder to use Oracle Clusterware would be passed to Product Management team and In support we don't have access to Product Strategy and the evaluations of various technologies when a particular component/technology is integrated with a product and hence cannot comment on it.

     

     

     

    Regards,

    Prakash.

  • 6. Re: High Availability in OracleAS
    JayaPrakash -Oracle Pro
    Currently Being Moderated

    Hi Jim,

     

    Could you please let us know if all the queries has been answered.

     

    So could you please mark whether this topic as helpful or requires more information.

     

    Regards,

    Prakash.

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