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Availability: Time Warp

Terry Critchley

"You can fool some of the people all of the time, and all of the people some of the time, but you cannot fool all of the people all of the time."
Abraham Lincoln

Some of the outage figures quoted by organizations look ludicrously small to me. Without casting aspersions on the veracity of these figures (or availability statistics), I do feel that some examination of them is needed.

The non-availability of a system is often quoted thus:

where MTTR is the Mean Time To Repair a particular outage.

”We recognized we'd run the wrong job and restarted correctly in just 3 minutes, thus our MTTR = 3 minutes."

If you substitute the word "recover" for "repair" in the above definition you will be closer to the truth. However, your database(s) are almost certainly on Planet Zog as far as consistency is concerned and the "repair" of that will often take much longer. The correct definition of MTTR should be "mean time to recover" and the equation then looks as above but with a new MTTR:

The last item in this equation I call the ramp up time, the time to get the show back on the road. This can be small but is often much larger than repair time, as shown in the diagram below. A decent Service Level Agreement (SLA) will opt for this definition of "fixed" for an issue and will include the ramp up time in the recovery time specification.

The recovery of a database or other data and metadata corrupted by human error or malware can take a considerable time to restore to the working status demanded by the end users.

This is borne out by several “Never Again” cases outlined in the Availability Digest (under the heading: Never Again) where financial bodies — banks, stock dealings — have repaired faults but taken many hours to recover normal working conditions again. ”The system was repaired at 11am and trading commenced normally at 2:30pm" is a typical (hypothetical) report on such situations.

The final point to make is that there are several viewpoints of an “outage” or period of "downtime", depending on your place in an organization. The end user's view will be that the outage lasts as long as he/she is prevented from using IT to do the job they are supposed to do. The server specialist's view might be that the outage of his hardware was a mere minute or two before it was fixed whereas the network person will say" “what's all the fuss about; everything on the network is working fine?”

It all depends on your viewpoint and I know what viewpoint the company CEO, the users and the board will take. Do you?

Dr. Terry Critchley is the Author of “High Availability IT Services” ISBN 9781482255904 (CRC Press).

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Availability: Time Warp

Terry Critchley

"You can fool some of the people all of the time, and all of the people some of the time, but you cannot fool all of the people all of the time."
Abraham Lincoln

Some of the outage figures quoted by organizations look ludicrously small to me. Without casting aspersions on the veracity of these figures (or availability statistics), I do feel that some examination of them is needed.

The non-availability of a system is often quoted thus:

where MTTR is the Mean Time To Repair a particular outage.

”We recognized we'd run the wrong job and restarted correctly in just 3 minutes, thus our MTTR = 3 minutes."

If you substitute the word "recover" for "repair" in the above definition you will be closer to the truth. However, your database(s) are almost certainly on Planet Zog as far as consistency is concerned and the "repair" of that will often take much longer. The correct definition of MTTR should be "mean time to recover" and the equation then looks as above but with a new MTTR:

The last item in this equation I call the ramp up time, the time to get the show back on the road. This can be small but is often much larger than repair time, as shown in the diagram below. A decent Service Level Agreement (SLA) will opt for this definition of "fixed" for an issue and will include the ramp up time in the recovery time specification.

The recovery of a database or other data and metadata corrupted by human error or malware can take a considerable time to restore to the working status demanded by the end users.

This is borne out by several “Never Again” cases outlined in the Availability Digest (under the heading: Never Again) where financial bodies — banks, stock dealings — have repaired faults but taken many hours to recover normal working conditions again. ”The system was repaired at 11am and trading commenced normally at 2:30pm" is a typical (hypothetical) report on such situations.

The final point to make is that there are several viewpoints of an “outage” or period of "downtime", depending on your place in an organization. The end user's view will be that the outage lasts as long as he/she is prevented from using IT to do the job they are supposed to do. The server specialist's view might be that the outage of his hardware was a mere minute or two before it was fixed whereas the network person will say" “what's all the fuss about; everything on the network is working fine?”

It all depends on your viewpoint and I know what viewpoint the company CEO, the users and the board will take. Do you?

Dr. Terry Critchley is the Author of “High Availability IT Services” ISBN 9781482255904 (CRC Press).

Hot Topics

The Latest

According to Auvik's 2025 IT Trends Report, 60% of IT professionals feel at least moderately burned out on the job, with 43% stating that their workload is contributing to work stress. At the same time, many IT professionals are naming AI and machine learning as key areas they'd most like to upskill ...

Businesses that face downtime or outages risk financial and reputational damage, as well as reducing partner, shareholder, and customer trust. One of the major challenges that enterprises face is implementing a robust business continuity plan. What's the solution? The answer may lie in disaster recovery tactics such as truly immutable storage and regular disaster recovery testing ...

IT spending is expected to jump nearly 10% in 2025, and organizations are now facing pressure to manage costs without slowing down critical functions like observability. To meet the challenge, leaders are turning to smarter, more cost effective business strategies. Enter stage right: OpenTelemetry, the missing piece of the puzzle that is no longer just an option but rather a strategic advantage ...

Amidst the threat of cyberhacks and data breaches, companies install several security measures to keep their business safely afloat. These measures aim to protect businesses, employees, and crucial data. Yet, employees perceive them as burdensome. Frustrated with complex logins, slow access, and constant security checks, workers decide to completely bypass all security set-ups ...

Image
Cloudbrink's Personal SASE services provide last-mile acceleration and reduction in latency

In MEAN TIME TO INSIGHT Episode 13, Shamus McGillicuddy, VP of Research, Network Infrastructure and Operations, at EMA discusses hybrid multi-cloud networking strategy ... 

In high-traffic environments, the sheer volume and unpredictable nature of network incidents can quickly overwhelm even the most skilled teams, hindering their ability to react swiftly and effectively, potentially impacting service availability and overall business performance. This is where closed-loop remediation comes into the picture: an IT management concept designed to address the escalating complexity of modern networks ...

In 2025, enterprise workflows are undergoing a seismic shift. Propelled by breakthroughs in generative AI (GenAI), large language models (LLMs), and natural language processing (NLP), a new paradigm is emerging — agentic AI. This technology is not just automating tasks; it's reimagining how organizations make decisions, engage customers, and operate at scale ...

In the early days of the cloud revolution, business leaders perceived cloud services as a means of sidelining IT organizations. IT was too slow, too expensive, or incapable of supporting new technologies. With a team of developers, line of business managers could deploy new applications and services in the cloud. IT has been fighting to retake control ever since. Today, IT is back in the driver's seat, according to new research by Enterprise Management Associates (EMA) ...

In today's fast-paced and increasingly complex network environments, Network Operations Centers (NOCs) are the backbone of ensuring continuous uptime, smooth service delivery, and rapid issue resolution. However, the challenges faced by NOC teams are only growing. In a recent study, 78% state network complexity has grown significantly over the last few years while 84% regularly learn about network issues from users. It is imperative we adopt a new approach to managing today's network experiences ...

Image
Broadcom

From growing reliance on FinOps teams to the increasing attention on artificial intelligence (AI), and software licensing, the Flexera 2025 State of the Cloud Report digs into how organizations are improving cloud spend efficiency, while tackling the complexities of emerging technologies ...