science

Virtual chargeback

Virtual chargeback is a science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Virtual chargeback rather than just read about it. In short: In information technology, virtual chargeback is a practice of charging back the costs of virtual IT infrastructure to departments or business units, that actually use it. This means analyzing and recording the resource utilisation on virtual machines (VMs).

Key takeaways

Virtual chargeback belongs to science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Virtual chargeback to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Virtual chargeback from memory before moving on to harder problems.

Reference excerpt

In information technology, virtual chargeback is a practice of charging back the costs of virtual IT infrastructure to departments or business units, that actually use it. This means analyzing and recording the resource utilisation on virtual machines (VMs).

Purpose The idea of chargeback in a traditional (non-virtualised) sense is not new, and references go as far back as the 1980s. Publications available on the Internet generally support the notion that chargeback involved charging departments based on actual resource consumption rather than forecast usage. Chargeback is most relevant to IT departments, simply because almost all areas of an organisation use computing resources. Rather than IT having to justify expenditures for another area of the organisation, the burden is on those departments who are actually planning on using the resource provided by IT. Virtual chargeback can be a particularly difficult process to implement, due to the use of shared/common resources. However, the internal implementation of a chargeback process usually resides between the application and infrastructure layers, which gives the data-collection services of the application the ability to pull from virtual or actual components. Reasons for using a chargeback model include: • More effective use of IT services due to customers becoming more conscious of the cost associated with new hardware and software • A better understanding of the TCO (total cost of ownership) for performing a business function • Prevention of business groups being charged for applications and services they rarely use • The entire IT infrastructure is taken into account (i.e. from network I/O through to storage)

Challenges While numerous tools exist for tracking asset utilisation in a traditional sense (such as Microsoft's Operations Manager), they are considered by some to be of limited use when it comes to virtual machines. Numerous attempts have been made to address this problem, some of which are available today:

VMware vCenter Chargeback, PlateSpin Recon, vKernel, Nicus M-PWR, Exivity, Hybrid Cloud metering & billing

See also Cost centre (business) Cost accounting IT chargeback and showback Time-sharing

References

Worked examples

Example 1 — a first encounter with Virtual chargeback

Start with the simplest possible case. Write down what Virtual chargeback claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Virtual chargeback before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Virtual chargeback ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Virtual chargeback

In research: Virtual chargeback appears in science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Virtual chargeback in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Virtual chargeback is common in secondary-school and first-year university syllabi. It links to neighbouring topics Information technology management, so understanding it makes those chapters shorter.
In everyday life: Look for Virtual chargeback outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Virtual chargeback in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Virtual chargeback means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Virtual chargeback out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Virtual chargeback in simple terms?

Why does Virtual chargeback matter?

Because it connects several science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Virtual chargeback?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Virtual chargeback.