If not already, then latest at TechEd 2016 it became obvious, that SAP have finally fully embraced their Cloud Strategy and Road Map.

Therefore, in this blog, I am sharing my experiences with setting up a performant and highly available SAP HANA Cloud Connector (SCC).

High Availability

For my high available SCC installation, I need a Master (Primary Installation):

And Shadow (Backup Installation) instance:

For this I extend the HANA, express edition architecture from my previous HANA Rules Framework (HRF) blog, by adding the two SCCs and access from the HANA Cloud Platform (HCP) through a List Report Application:

Originally, I intended to call HRF Rules Services from the HCP but it turned out to be more practical to call an OData service from the SAP HANA Interactive Education (SHINE) content. Therefore, I configure the respective connectivity in my Master SCC:

In a multiple HANA database container environment like mine, it is important, that my Virtual Host concurs with my database tenant HTTP and HTTPS settings. If I chose a different virtual host, epmhost in this example, the HANA Web Dispatcher would not know where to connect to:

On the basis of my SCC configuration I create a Destination in the HCP:

And check it respectively:

Now I can use this connection in my List Report Application to connect to the PO_WORKLIST collection:

As a result, I see all the POs from the SHINE content in my List Report Application:

To add high availability, I have to configure my Master SCC to enable High Availability Through my Shadow SCC:

Next I configure my Shadow SCC respectively and connect to my Master SCC:

When I now shutdown my Master SCC this is recognized by my Shadow SCC after the Check Interval period and is Attempting to take over after counting down the Takeover Delay period:

As a result, my Shadow SCC has become my Master SCC and my connection from the HCP continues to work seamlessly. Once restarted, my former Master SCC resumes the role of Shadow SCC. If I did not like this, I could always switch back the roles again:

Sizing

On the one hand side, there are no guidelines concerning the sizing of a SCC installation from SAP yet, that I would be aware of. Instead, if you were running your environment virtualized on VMware like I do, you could refer to the SAP On VMware Best Practices guide.

On the other hand, the SCC is just a java process running natively on the operating system without the need for any form of SAP application server:

Therefore, general Java sizing guidelines apply and in my scenario, all except one request have been delivered in less than 125ms:

Finally, the SCC Hardware Metrics would give me an indication if Disk Space, Java Heap, Physical of Virtual Memory became a bottleneck which they currently do not:

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6 Comments

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  1. Douglas Cezar

    Hi Frank, how are you doing?

    Congratulation for the nice blog, rich in details!

    I’m researching options to connect my ABAP on premise backend to my tril HCP account so I can consume data in my Fiori app.

    Since I’m a developer guy and don’t master the more deep aspects of the connect I have this doubt after reading your text: when I use SCC is it needed to also have Web Dispatcher? I was thinking that web dispatcher should be replace by SCC, so isn’t that the case?

    Thank you and best regards,
    Douglas

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    1. Frank Schuler Post author

      Thank you Douglas,

      Strictly speaking, the SCC does not replace the Web Dispatcher.

      However, to connect your HCP trial account to your on premise ABAP system, you don not need a Web Dispatcher, but only a SCC.

      Best regards

      Frank

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      1. Douglas Cezar

        Hi Frank, thank you very much for your reply.

        Let’s say that later I deploy my app from HCP to the ABAP UI5 respository and want mobile devices to access data when those devices are outside my corporate network. In this case Web Dispatcher will be needed or  SCC will still be enough?

         

        Thank you again,

        Douglas

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        1. Frank Schuler Post author

          Hello Douglas,

          in your scenario the SCC will have no role after the deployment of your app to the ABAP UI5 repository any longer except for accessing it from the WebIDE for fixes or improvements.

          For secure access to this app from outside your corporate network, you would need some sort of reverse proxy. In your scenario the Web Dispatcher could be a good choice because it connects naturally to the SAP ABAP application server by inspecting its properties.

          Best regards

          Frank

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  2. Iliyas Niyazi

    Dear Frank,

    Thanks for nice blogs.

    We are planning to have HA a DR for our SCC server, with regards we have couple of questions.

    What is the best approach to achieve HA and DR

    1. Master and Shadow Approach

    1.a) Installing a Failover Instance for High Availability using Master and shadow approach: We understood the master pushes the config changes data to shadow on a regular basis.

    Question1: Master is running on Hostname A and shadow is running on HostnameB and the HCI is connected to primary server HostnameA. When the switch happens from master to shadow how my HCI will know my active server is HostnameB.

    Questiion2: How the DR server will be sync and what changes required at HCI and SCC level to run our operations from DR

    2) VM HA is supported for SCC

    Thanks for your reply

    Regards

    Iliyas.

     

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    1. Frank Schuler Post author

      Hello Iliyas,

      1. Question 1: The connection to HCI is always invoked from the SCC. Once the Master SCC becomes unavailable the Shadow will connect to HCI. From a HCI perspective, this is transparent.
        Question 2: You can use your Shadow SCC also as your DR, if you place it in a secondary data centre that has connection to your primary data centre.
      2. Yes, you can use for example VMware HA with SCC.

      Best regards

      Frank

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