Collected thoughts about software and site performance ...

Web performance matters. Responsive sites can make the online experience effective, even enjoyable. A slow site can be unusable. This site is about online performance, how to achieve and maintain it, its impact on user experience, and ultimately on site effectiveness.

Home | Entries about Standards (Apdex, ITIL, etc.) (10), in reverse date order:

Generalizing The Apdex Standard [2]

Illustration: Apdex Logo

Today the Apdex specification is entirely focused on application response time. Its first paragraph defines Apdex as “a method for calculating and reporting a metric of transactional application response time in the form of an index with a value of 0 to 1.” But in reality, the Apdex method has much wider applicability. A more appropriate description might be the general statement that Apdex is a metric that reflects the degree to which a set of performance measurements achieves designated targets.

The idea of generalizing the Apdex standard has been discussed periodically within the Apdex community. To turn those discussions from an abstract idea into a concrete proposal, I’m writing a series of posts on the Apdex Exchange blog ...

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Apdex as a (Key) Performance Indicator

Illustration: Apdex Logo

On the Apdex Exchange blog, I’m writing a series of posts about Generalizing The Apdex Standard. The ideas I developed (together with any public input) will evolve into a new draft of the Apdex specification. The latest post is on Apdex as a (Key) Performance Indicator. Here's a brief introduction:

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Measuring Mobile Web Sites

Illustration: Web Analytics Report

The methods commonly used to measure Web sites often don't work for mobile sites, because of differences among mobile platforms and devices. The biggest obstacles are lack of support on mobile devices for Cookies, JavaScript, and client IP addresses.

The Wikipedia article on Mobile Web Analytics provides a succinct introduction to these and other challenges -- see the section on "Problems with tracking visitors, visits and clickpaths in the Mobile Web". Because of these limitations, the tagging methods used by traditional Web analytics tools do not work on most mobile devices.

While researching this subject, I discovered Kaizen Analytics, an excellent blog by Michael Notté. In a recent post, Michael provides a useful overview -- see Mobile Analytics: vertical-specific vs. traditional Web Analytics solutions. Michael points out that there are other ways to collect data about mobile Web sites. He outlines four solution approaches, illustrating each with a helpful diagram:

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Choosing Performance Management Tools

Illustration: Apdex Logo

With over 30 application performance management (APM) tool vendors offering scores of products, buyers face hundreds of confusing choices. Compounding the problem, the lack of a common taxonomy, or standard APM nomenclature, makes cross-vendor product comparisons especially challenging.

To address this challenge, NetForecast has developed an APM tools framework anyone can use to define APM requirements and map them to vendor offerings. On June 30 2010, Peter Sevcik will describe this framework in a Webinar hosted by the Apdex Alliance ...

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Service Level Management with Apdex

Illustration: Apdex Logo

Service level management (SLM) is the art and science of keeping application services running properly once in production. The key to successful SLM is the ability to use metrics that are linked to the business.

Apdex (Application Performance Index) is an open standard that is a numerical measure of user satisfaction with the performance of enterprise applications. It converts many measurements into one number on a uniform scale of 0-to-1 (0 = no users satisfied, 1 = all users satisfied).

Properly implemented, Apdex enables an organization to link application performance to business needs ...

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Generalizing The Apdex Standard

Illustration: Apdex Logo

Today the Apdex specification is entirely focused on application response time. Its first paragraph defines Apdex as “a method for calculating and reporting a metric of transactional application response time in the form of an index with a value of 0 to 1.”

But in reality, the Apdex method is much more widely applicable, and a more appropriate description is already spelled out in the first paragraph of the Wikipedia article on Apdex ...

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Where Performance Meets Availability

Illustration: Stopwatch

Earlier posts about Acceptable Response Times have discussed how a Web site or application's responsiveness can Delight, Satisfy, or Frustrate customers.

Availability, on the other hand, is a measure of a system's stability. It is not a performance metric, it is a software (or hardware) quality metric.

So, technically speaking, performance and availability are orthogonal issues. Practically speaking, however, availability and responsiveness are interconnected concepts.

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ITIL Crash Course

ITIL logo

Anyone involved with IT these days knows that ITIL is a hot topic, and one that seems to get hotter every month. ITIL, the Information Technology Infrastructure Library, has evolved from work sponsored by the UK Government in the late 1980's. According to the official ITIL site, it is "the most widely accepted approach to IT service management in the world".

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The Value of Reference Models

Illustration: Tower of Babel

Without a shared language, communication is impossible. A reference model establishes a shared foundation -- a frame of reference, or conceptual framework -- that can then be used to structure subsequent discussions of a subject. For more details online, the best resource I found is a discussion of the OASIS SOA Reference Model. Its focus is different from ours, but it contains some good general points, including:

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Apdex: Application Performance Index

Illustration: Apdex Logo

Yesterday I introduced the subject of Web Performance Management. [Note: I have since rewritten that material as the Performance Topics page]. To manage application service levels effectively, and satisfy your customers, you must monitor and report on availability and response times. So if you collect 10,000 measurements, what's the best way to report them?

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