Demystifying SRE (Site Reliability Engineering)

Explore SRE (Site Reliability Engineering): Your guide to understanding Site Reliability Engineering’s transformative impact on software management.



How Site Reliability Engineering Keeps Web Apps Running Smoothly


Technology has revolutionised service delivery and significantly improved user experience for both customers and service provision teams alike. But have you ever wondered how some apps seem to work like a charm while others drive you nuts and are frequently down?

Several factors influence this, with a major one being SRE (Site Reliability Engineering). With roots in the DevOps principle of infrastructure-as-code, SRE saves developer time, standardised provisioning, and fortifies against disruptions.

Downtime costs a huge amount of resources and money. Gartner reported that the average cost of downtime was $5,600 per minute, with another study by Avaya putting it at $2,400 to $9,000 per minute.

Although downtime costs may vary, the implications are clear. Implementing SRE (Site Reliability Engineering) best practices in your organisation can save costs and heighten user satisfaction. So, let's demystify SRE and help you easily digest its core components and how to reap the benefits.

Understanding SRE (Site Reliability Engineering)

At its core, SRE is about making things work smoothly and keeping them that way. It's based on a few key principles:

  1. Embracing Risk: SRE emphasises risk management rather than risk avoidance. It calls for balancing rapid innovation with system reliability. This is done through defining error budgets, which are acceptable risk levels agreed upon for the system[1].
  2. SLOs (Service Level Objectives): SLOs form the backbone of the SRE approach. These are the quantifiable targets set representing the desired level of system performance and reliability[1].
  3. Eliminating Toil: Toil is repetitive and mundane work offering little value. SRE focuses on automating operations and tasks to streamline operations and free up resources for problem-solving[2].
  4. Monitoring Systems: Continuous monitoring of distributed systems is a key principle of SRE. It enables real-time anomaly detection and facilitates prompt incident response[3].
  5. Shared Ownership: The responsibility of maintaining system health is shared across cross-functional teams - bridging the gap between development and operations[4].
  6. Blameless Culture: Post-mortems in SRE are blameless - focused on learning from incidents and improving the system, fostering a culture of trust and continuous learning[5].

SRE's primary objective is to ensure optimal system reliability, scalability, and performance, fostering cohesion and harmony instead of warring factions. It's not merely about addressing issues as they arise but strategically working to foresee and neutralise potential pitfalls. This proactive approach is what makes SRE an unparalleled asset in the IT world. If you’re familiar with ITIL, SRE covers problem, incident, change, service level, availability and capacity management pillars.

Core Components of SRE

Now you have an understanding of SRE, let's get into the core components.

Error Budgets 

Error budgets serve as a strategic tool in SRE. If you’ve promised 99.9% uptime, your service should only have a downtime of around 4.5 minutes per month. That's your error budget! If your downtime exceeds this limit, deploying new features will have to be postponed until the system stabilises. This technique aids in balancing innovation, improves system reliability, and helps maintain smooth application performance.


Monitoring involves observing metrics to gauge the behaviour and overall health of software in a production environment. Using dedicated monitoring tools, commonly tracked metrics include:

  • Latency – The time taken from when a request is made until the application responds. 
  • Errors – This metric indicates the number of instances where the application fails to perform a given task.
  • Traffic – This refers to the number of people using your application at any given time. 
  • Saturation – Saturation indicates how much work the application can do in real time. High saturation means the application can’t perform as well as you’d like. 

Incident Response and Management 

This is about identifying, addressing, and mitigating issues that occur during the running of an application. The process involves decision-making on incident prioritisation, solution choices, and escalation requirements.

For example, if a module in charge of processing e-commerce payments for a specific bank card is failing, the SRE team may consider how many people use it before sorting it out. Then, they may start working on a solution, but if it's taking too long because it involves action from a third party, they may first turn off the feature entirely. However, they could simply give it more processing power and memory if it's just overloaded.


Automation is a cornerstone in SRE, where recurrent operational tasks are assigned to automated processes. This could include provisioning infrastructure, feature deployment, load balancing, data backups, and updates. The key is understanding which operations should be automated based on their predictability and regularity.

Site reliability engineering aligns with business objectives

SRE (Site Reliability Engineering) helps to align business objectives by balancing reliability and innovation for your business excel. By limiting downtime via error budgets, SRE ensures optimal user experience and protects your company's reputation, which will strengthen customer trust and boost their satisfaction.

In addition, SRE prioritises efficiency through automation and organised incident management, enabling teams to focus on higher-value tasks and improvements. This brings quicker development of new features and services to provide a competitive edge in the market. SRE's data-driven and proactive approach enables businesses to anticipate future challenges and make informed decisions, resulting in more robust and agile systems.

SRE vs. Traditional Operations

In traditional IT operations, team members pay more attention to aspects like server maintenance and are less involved in processes like ideation for new features or coding. SRE team members, on the other hand, will often find themselves contributing to software creation and actively working towards strategising server efficacy. 

Traditional IT subtly slips into the background post-deployment, reaching out to developers when trouble hits or when everything rolls out nicely. In contrast, SRE teams are in constant sync with developers even before the deployments happen.

Traditional IT operations can be heavy on manual tasks to manage infrastructure, whereas SRE teams lean to automation for a considerable amount of their work. Development and operations have a considerable amount of work on both sides, so automation keeps things moving smoothly and efficiently.

Benefits of Site Reliability Engineering:

  • Faster Incident Resolution: 

SRE employs streamlined processes and advanced tools that help in the quick identification and rectification of system issues. This results in significantly reduced downtime and prevents possible loss of revenue and productivity. By following DevOps practices and fostering better communication between development and operations teams, SRE ensures a smooth flow of information that expedites problem-solving.

  • Proactive Problem-Solving: 

One of the major benefits of SRE is its emphasis on proactive measures. Through rigorous system monitoring and intelligent data analysis, potential issues are detected early. Solving these problems before they escalate minimises disruptions to the service and enhances overall system reliability.

  • Enhanced User Experience: 

SRE plays a pivotal role in ensuring a robust and reliable system that translates into a seamless user experience. By maintaining high system uptime, ensuring swift incident resolution, and promoting system improvements, SRE contributes to user satisfaction and fosters user trust and loyalty. In an era where user experience significantly influences business success, this proactive approach to user satisfaction is invaluable.


Site Reliability Engineering Workflow and Practices

Now you know what SRE is, what it does, and the benefits it brings; what is the best way to implement it? An SRE workflow alongside SRE best practices. Let’s discover how.


SRE workflow

An SRE workflow is a systematic approach aimed at continuous improvement and upholding system reliability. Here's a detailed breakdown:

  • Define SLOs (Service Level Objectives): 

This is the first step, where reliability goals are set for the system. SLOs are quantifiable key performance metrics defining what a good user experience looks like in terms of availability, latency, and system performance.

  • Monitor and Measure: 

After defining SLOs, this then determines the Service Level Indicators (SLIs) to rigorously monitor the system’s performance against these objectives. Advanced monitoring tools and techniques are used to procure real-time data about system health.

  • Establish Error Budgets: 

An error budget is the maximum acceptable level of unreliability agreed upon, mirroring the balance between system reliability and innovative feature release. It's the calculated risk taken in pushing new updates vs. maintaining the system's reliability.

  • On-call Rotations for Incident Response: 

In the event of a system failure or performance issue, on-call SRE team members take immediate action. Rotating on-call duties among team members ensures round-the-clock coverage without overworking anyone.

  • Incident Resolution: 

SRE teams follow systematic incident resolution procedures including identification, diagnosis, containment, correction, and recovery stages to handle system issues effectively.

  • Conducting Post-Incident Analysis: 

Once the issue gets resolved, the team conducts a blameless post-mortem analysis where they dissect the incident to understand its root cause, what went wrong, and what actions could prevent similar incidents in the future.

  • Iterative Improvement: 

All the insights from the post-incident analysis are then transformed into actionable improvements in the system and process, thereby enhancing reliability and performance over time. It's an ongoing, cyclical process that is integral to SRE workflow.

Each step in the workflow is crucial, guiding your team to maintain a balance between reliability and innovation while continuously improving the system.


SRE best practices

Implementing best practices in SRE is essential in order to maintain system reliability, learn from incidents, and streamline on-call responsibilities. Here are some proven best practices for each aspect:

Managing On-call Rotations:

  • Define on-call roles and expectations.
  • Create a fair rotation schedule.
  • Employ on-call scheduling tools.
  • Enable training and knowledge sharing.

Conducting Blameless Postmortems:

  • Cultivate a blameless, learning-oriented culture.
  • Make postmortems a mandatory process post-incident.
  • Thoroughly analyse root causes and incident timelines.
  • Identify, propose, implement, and track improvements.
  • Some teams also find that performing post-mortems after a significant release is also a useful practice. Even if it went well.

Continuously Improving System Reliability:

  • Set and periodically update realistic SLOs.
  • Use robust monitoring for real-time anomaly detection.
  • Proactively analyse and optimise system performance metrics.
  • Learn and implement changes from each incident or near miss.
  • Automate repetitive tasks to avoid errors and increase efficiency.
  • Regularly invest in team training and skill development.

Following these SRE best practices will enable you to strengthen your SRE strategies, streamline on-call responsibilities, conduct effective postmortems, and continuously improve system reliability.


How SRE best practices have helped various organisations

Site Reliability Engineers have massively helped LinkedIn transition to a microservices architecture with minimal breakdowns, enabling the organisation to scale further and be more available to a larger user base even with an intricate, distributed infrastructure setup. 

Etsy, a popular e-commerce marketplace for handmade crafts and vintage items, has used Site Reliability Engineering practices to improve monitoring and alerting, reducing downtime during cloud migration by getting ahead of issues before they lead to outages.

SRE practices have also helped Netflix harness automation to detect and respond to incidents appropriately. This has kept the company ranking high in the list of highly available global video streaming services. You can learn more about real-world SRE triumphs here

You can also learn more about how Mesoform has applied automation to manage the influence of security on application reliability in a compliance enforcement solution


The relationship between DevOps and SRE

DevOps and SRE relationship may initially seem focused on different aspects - one on speedy, high-quality software delivery, the other on upholding software reliability. Yet, when these two come together, they can power up software development and operations.

A DevOps team may be proficient at developing chunks of software swiftly, but an SRE team helps make sure this rapid output doesn’t upset system stability. They do so by extending the existing automation stack. If a DevOps team automates parts of coding and testing, the SRE compliments it by automating operations and certain deployment processes.

The SREs employ powerful tools to oversee performance in production settings and promptly respond to incidents. This means while they might not share DevOps' speed obsession, their mutual goal is stability. That shared objective fosters collaboration.

This teamwork ensures a thorough understanding of system limits and readiness to operate at maximum safe enhancements. This can be through crafting resource-efficient code, vigilantly monitoring systems, tweaking targets, or prioritising certain updates. The result? A business model that continues to expand its service and client portfolio, underpinned by reliability.


Wrapping Up

All-in-all, SRE encourages reliance on automation to perform operations tasks faster and more accurately, implementing changes in small continuous doses and always observing system behaviour keenly. By adopting SRE practices, you can anticipate slowdowns and failures, prevent many of them, and fix the others quickly, eventually enhancing your application's reliability. 

You can learn more about the benefits of SRE (Site Reliability Engineering), how it relates to other practices, and how to get it right by checking out our resources and visiting our social media pages.   

If you would like to discuss any of these topics in more detail, please feel free to get in touch

About Mesoform

For more than two decades we have been implementing solutions to wasteful processes and inefficient systems in large organisations like TiscaliHSBC and HMRC, and impressing our cloud based IT Operations on well known brands, such as RIMSonySamsung and SiriusXM... Read more

Mesoform is proud to be a