My ramblings about all things technical

VCAP6-CMA Design Objective 2.5 – Build Performance Requirements into the Logical Design

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Evaluate logical performance considerations for a given vRealize Automation solution.

Performance considerations will be the number of virtual machines the solution has to provide sufficient resources for as well as future growth (20% growth over the next 3 years) . This is very much like vSphere sizing but now with the speed with which solutions can be created, modified and deleted especially if you are doing CDCI you need to also prepare for the number of continuous deployments and workflows at once. For example a DEM worker can only process 15 concurrent workflows at a time so if you are likely to be doing 60 workflows simultaneously due to the lifecycle of your machines then you are going to need at least four DEM workers to be deployed to handle this.

Performance also entails using mechanisms such as Storage DRS to automatically load balance provisioned workloads as they are requested, DRS to load balance the workloads across the hosts in the solution and performance of the vRA management components by isolating them in a management cluster, ensuring they are load balanced so one side isn’t always hit and the other is doing nothing. They don’t mention it in the tools but for this section and the exam as a whole I would recommend reading the latest vCAT documentation as well as the vRA 6.2 Reference Architecture document .

Differentiate infrastructure qualities related to performance.

Just like I have mentioned for the availability and management sections, the infrastructure quality for performance will need to be applied to certain requirements and designs decisions in the exam via drag and drop questions (I have done the exam so I am basing this on experience) . The performance infrastructure quality is defined as:

Indicates the effect of a design choice on the performance of the environment. This does not necessarily reflect the impact on other technologies within the infrastructure.

Key metrics:

  • Response time
  • Throughput

Analyze the current performance of an environment and address gaps when building a logical design.

So this is down to you deploying the vRA solution in an existing environment where there are workloads running and you need to analyse the performance of the environment to ascertain if the environment meets the performance requirements or if additional resources/another environment is required for the solution to work.

There are a number of methods to do this:

  • Get a VMware partner or VMware to run an analysis via VMware Capacity Planner to work out what your current environment is doing.
  • Use vRealize Operations Manager to give you a current state analysis as well as use historical data to work out trends and if there are month end increases in performance requirements or seasonal increases depending on the company’s business.
  • vSphere performance charts can also give you a not bad idea of what is happening if the above two aren’t possible as well as 3rd party tools.

Use a conceptual design to create a logical design that meets performance requirements.

In the conceptual design you will have defined and signed off the requirements. In these requirements there should be a number of them that apply to the performance infrastructure quality for example “The solution must be able to support the provisioning of 500 workloads a day” and “the solution must be able to service 5000 workloads with a 20% increase year on year for the next five years”

You will also have requirements where due to BC/DR requirements you will need spare capacity in the event of a failure so for example “The production workloads in Site A which makes up 20% of the 5000 workloads need to run on the secondary site in the event of a planned or emergency failover” .

Determine performance-related functional requirements based on given non-functional requirements and service dependencies.

Non-functional requirements are normally constraints imposed by the customer so for example the customer has defined you have to use existing networking in the datacentres and these are only 1GB switches which will severely impact what is possible from the solution. So if we keep to my example then having a service dependency that needs to talk to a physical SQL server where large amounts of data is transferred between the services to the database a single 1 GB link won’t be sufficient so either the service will have to be scaled down or the SQL database created as part of the service to allow inter virtual switch connectivity thereby allowing higher network throughputs.

Define capacity management practices and create a capacity plan.

For the exam they are looking for you to define this via the reservations on the compute resources to ensure capacity doesn’t run out. Fellow Xtravirt colleague Craig Gumbley has defined this nicely in relation to the VCP6-CMA blueprint

Incorporate scalability requirements into the logical design.

This has been covered above already but what they are looking for is for you to design for future growth of the environment as the number of workloads increases and/or the amount of workload requests increases. The vRealize Automation reference architecture document also gives great coverage of scalability

Determine a performance component for service level agreements and service level management processes.

I covered this in the availability section where you have done a business impact analysis and worked out what theirs RPO and RTO values are. Part of availability also ties into performance as if the solution is running so slowly that users can’t use it then the service is essentially down and SLA’s are possibly not being met.





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