Server, storage and network virtualization (vLANs) is becoming more common place where real benefits of Cloud Computing slowly but surely advance from hype to reality. Expectations and promises for big cost savings and efficiency gains are huge and yet essential details for how to do security, performance, achieve high availability, perform QA, backups and many other common IT deployment and operations tasks continue to lag.
Yes, it is relatively easy to move a simple, self-contained application into let’s say a public cloud, but how would you know it to be ready for productive use? There are a lot of IT operation puzzle pieces to be worked out for the new virtualization and cloud trends to make them really useful. Luckily the SAP Co-Innovation Lab (COIL) (http://coil.sap.com/) is a place where SAP’s partners and SAP can join together to work out some new best practices for the emerging new IT environments.
For a recent Proof of Concept (POC) project we emphasized two tasks at once with SAP partners HP and Shunra. The POC topic is the stress testing of an application and the performance of applications across a wide area network. For stress testing the HP LoadRunner tool, which is also resold by SAP, is very well known; but in this instance, we added two more twists to it:
- That HP LoadRunner can be deployed and run from within a virtual machine sounds likely but would it yield the same stress test results compared to HP LoadRunner directly installed on a physical server? Would response times and error rates measured be the same?
- What about the latest HP LoadRunner WAN emulation features provided through integration with Shunra’ s technology (note: integration made available beginning with HP LoadRunner version 9.5). Does the software based WAN emulation work when deployed inside a virtual machine? Again, would test results be the same as with the hardware appliance based WAN emulation Shunra offers as well?
Such questions are important to answer simply because if you move your application into a virtualized environment you don’t want to lose efficiency again by having your test tools deployed directly to physical servers or as dedicated appliances, physically wired into your datacenter. If you plan to move applications into an off-premise cloud then you might not even have the option of physical deployment of software and hardware solutions any longer!
Why pay attention to WAN emulation? First of all, even for conventionally deployed and operated business applications, most end-users are no longer working in the same (local area network, LAN) location where the application is running . As we’ve previously described in an earlier paper, the long distance connectivity over a wide area network (WAN) has a very significant performance impact on business applications. With the next stage of evolution – SaaS and collaborative apps like LinkedIn or SAP Streamworks, the notion of application and infrastructure as separately installed and operated, and most importantly performance and cost optimized entities begins to break down. Only if applications with their infrastructure together are treated as one combined product can real optimization be achieved and yield a profit for SaaS offerings. Consequently, with the continuous proliferation of virtualization leading to clouds a combined application plus its wide area network overall solution testing is required and the HP LoadRunner/Shunra combination is one tool which can help (see also Shunra’s blog).
To make the rest short: We explored testing of a simple SAP application scenario with HP and Shunra in COIL and found:
- There is no detectable difference in test results using physical vs. virtual deployments of HP and Shunra testing products!
- We derived a best practice testing methodology for not only finding problems of a combined application/WAN infrastructure solution but also for verifying solutions to in particular the WAN induced performance issues. Application and network groups can now use the same test set-up and environment to optimize a business solution together, cutting out a lot of redundancies if those groups would work separately.
Of course we documented our findings in a white paper which you can find here http://www.sdn.sap.com/irj/scn/index?rid=/library/uuid/90679c93-6653-2d10-a0af-faf3fdc22883.