There is an SLO document in your organization that promises four nines of availability, was written to sound impressive in a planning meeting, and has been quietly breached every month since. Nobody acts on the breach because everybody knows the target was aspirational. The SLO exists, it is missed routinely, and it has trained the team to ignore it, which is worse than having no SLO at all.
This is more than an over-ambitious number. It is a failure of how the SLO was set and operated.
A service level objective your team can actually hit is more than a high number on a slide. It is a target grounded in a meaningful service level indicator, set at a level the system can realistically meet, with an error budget that drives real decisions, so the SLO is a tool the team uses rather than a promise it breaks.
However, many teams pick aspirational numbers to look good and discover that an SLO nobody can hit is an SLO nobody respects.
If you are an engineering or platform leader responsible for reliability targets, the intent of this article is:
- Define what makes an SLO achievable and useful
- Walk through choosing indicators, targets, and error budgets
- Lay out the operating model that makes SLOs drive decisions
To do that, let's start with the basics.
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What Is a Service Level Objective? The Basic Definition
At a high level, a service level objective is a target for a measurable indicator of service health, chosen at a level the system can realistically meet, with an error budget, the allowed shortfall, that the team uses to balance reliability against change.
To compare:
If a vanity SLO is a New Year's resolution to run a marathon next week, an achievable SLO is a training plan calibrated to your current fitness. One sounds impressive and gets abandoned; the other gets followed because it is real.
Why Are Achievable SLOs Necessary?
Issues that achievable SLOs address or resolve:
- Replacing aspirational numbers nobody hits with targets that guide behavior
- Giving the team an error budget to balance reliability and velocity
- Tying reliability decisions to data rather than opinion
Resolved Issues by Achievable SLOs
- Turns reliability from a vague goal into a measured target
- Provides an error budget that drives concrete decisions
- Restores respect for the SLO by making it meetable
Core Components of a Good SLO
- A meaningful service level indicator tied to user experience
- A realistic target the system can meet
- An error budget derived from the target
- An operating model that acts on budget consumption
- Review and adjustment as the system and needs change
Modern SLO Tools
- Prometheus and Grafana for SLI measurement and SLO tracking
- Datadog, Honeycomb, and similar with built-in SLO features
- Error budget dashboards and burn-rate alerting
- Incident tooling tied to budget consumption
- Observability platforms supplying the underlying signals
These tools track and operationalize SLOs, but the value comes from choosing the right indicator and a realistic target.
Other Core Issues They Will Solve
- Give product and engineering a shared language for reliability
- Provide an objective basis for the reliability-versus-velocity tradeoff
- Surface reliability regressions before they become outages
Importance of Achievable SLOs in 2026
Useful SLOs matter more as reliability becomes a product feature and a contractual expectation. Four reasons explain why it matters now.
1. Vanity SLOs erode trust in the practice.
An SLO that is missed every month teaches the team to ignore it. The practice only works when the targets are real.
2. Error budgets resolve a recurring argument.
The reliability-versus-velocity debate is endless without data. An error budget turns it into a decision: budget remaining, ship; budget spent, slow down.
3. Reliability is now a differentiator.
Customers and contracts increasingly expect stated reliability. SLOs are how teams set and meet those expectations deliberately.
4. Over-targeting is expensive.
Chasing more nines than the use case needs burns engineering effort. Achievable SLOs set reliability where it is actually worth the cost.
Traditional vs. Modern Reliability Targets
- Aspirational numbers vs. targets the system can meet
- Reliability as a vague goal vs. a measured SLI and error budget
- Velocity debates by opinion vs. decisions driven by budget
- Set once and ignored vs. reviewed and adjusted
In summary: A modern SLO is realistic, measured, and operationally used, not an impressive number that gets quietly missed.
Details About the Core Components of an SLO: What Are You Designing?
Let's go through each element.
1. Indicator Layer
What you measure.
Indicator decisions:
- An SLI tied to actual user experience
- Availability, latency, or correctness as appropriate
- Measured where the user feels it, not deep in the stack
2. Target Layer
The level you commit to.
Target decisions:
- A target the system can realistically meet
- Grounded in historical performance
- Set to what the use case needs, not the maximum nines
3. Error Budget Layer
The allowed shortfall.
Budget decisions:
- Budget derived from the target
- Tracked and visible
- Burn rate alerted on
4. Operating Layer
How the budget drives decisions.
Operating decisions:
- Budget remaining permits change and risk
- Budget exhausted triggers a reliability focus
- The rule agreed in advance, not argued mid-incident
5. Review Layer
How SLOs evolve.
Review decisions:
- Targets revisited as the system and needs change
- Misses analyzed for cause
- SLIs refined as understanding improves
Benefits Gained from Realistic Targets and Error Budgets
- An SLO the team respects because it can be met
- An error budget that settles the reliability-versus-velocity tradeoff with data
- Reliability set where it is actually worth the cost
How It All Works Together
You choose an indicator that reflects what users actually experience and set a target the system can realistically meet, grounded in its history and in what the use case needs. From that target comes an error budget: the allowed shortfall. The team agrees in advance how the budget drives decisions, ample budget permits shipping and risk, an exhausted budget triggers a focus on reliability. Burn-rate alerts surface trouble early. The SLOis reviewed as the system and needs change. Because the target is real and the budget drives concrete decisions, the SLO becomes a tool the team uses rather than a promise it breaks.
Common Misconception
A higher SLO target is a better SLO.
A higher target is only better if the system can meet it and the use case needs it. An unachievable target is missed routinely and ignored, and chasing unnecessary nines burns effort. The best SLO is the one set at the right level, not the highest.
Key Takeaway: An SLO you cannot hit is worse than no SLO, because it trains the team to ignore the practice. Realistic beats impressive.
Real-World SLO Implementation in Action
Let's take a look at how achievable SLOs operate with a real-world example.
We worked with a team whose aspirational SLOs were breached every month and ignored, with these constraints:
- Set targets the system could realistically meet
- Use error budgets to drive real decisions
- Restore the team's respect for the SLO practice
Step 1: Choose Meaningful Indicators
Measure what users actually experience.
- SLIs tied to user experience chosen
- Measured where the user feels it
- Vanity metrics discarded
Step 2: Set Realistic Targets
Ground the target in reality and need.
- Historical performance reviewed
- Target set to what the use case needs
- Unnecessary nines avoided
Step 3: Derive and Track the Error Budget
Turn the target into an operational budget.
- Error budget derived from the target
- Tracked on a visible dashboard
- Burn-rate alerting set
Step 4: Agree the Operating Rule
Decide in advance what the budget triggers.
- Ample budget permits change and risk
- Exhausted budget triggers reliability focus
- Rule agreed before any incident
Step 5: Review and Adjust
Keep the SLO honest over time.
- Targets revisited as the system changes
- Misses analyzed for cause
- SLIs refined with experience
Where It Works Well
- Indicators tied to real user experience
- Targets the system can meet, set to actual need
- Error budgets that drive agreed, concrete decisions
Where It Does Not Work Well
- Aspirational targets breached every month and ignored
- SLIs that do not reflect what users feel
- Error budgets tracked but never acted on
Key Takeaway: The SLO the team uses is the one with a realistic target and an error budget that drives decisions, not the impressive number that gets quietly missed.
Common Pitfalls
i) Aspirational targets
A target the system cannot meet is missed routinely and ignored, eroding the practice. Set targets grounded in reality and need.
- Base targets on historical performance
- Match nines to the use case
- Avoid vanity numbers
ii) Meaningless SLIs
An indicator that does not reflect user experience produces an SLO that can be met while users suffer. Measure what users feel.
iii) Error budgets nobody acts on
A tracked budget that triggers no decisions is decoration. Agree in advance what budget consumption changes.
iv) Set-and-forget
An SLO never revisited drifts from reality as the system changes. Review targets and refine SLIs over time.
Takeaway from these lessons: Most SLO failures trace to unrealistic targets and unused budgets, not to measurement. Set meetable targets, choose real indicators, and act on the budget.
SLO Best Practices: What High-Performing Teams Do Differently
1. Choose indicators users feel
Measure availability, latency, or correctness where the user experiences it. An SLI disconnected from experience produces a meaningless SLO.
2. Set targets you can actually hit
Ground targets in historical performance and the use case's real needs. Realistic beats impressive every time.
3. Make the error budget drive decisions
Agree in advance that ample budget permits velocity and an exhausted budget triggers reliability focus. The budget is the point.
4. Do not over-target
More nines cost more effort. Set reliability where it is worth the cost, not at the maximum for its own sake.
5. Review and refine
Revisit targets and SLIs as the system and needs change. An SLO is a living tool, not a one-time declaration.
Logiciel's value add is helping teams choose meaningful indicators, set realistic targets, and operationalize error budgets, so SLOs become tools the team uses to balance reliability and velocity rather than promises it breaks.
Takeaway for High-Performing Teams: Focus on realistic targets and an error budget that drives decisions. An SLO is useful only when it is meetable and acted upon; an impressive number that is routinely missed is worse than none.
Signals You Are Setting SLOs Correctly
How do you know the SLO practice is set up to succeed? Not in the height of the targets, but in whether the team uses them. Below are the signals that distinguish useful SLOs from vanity ones.
The targets are usually met. The team hits its SLOs most of the time, because they were set at an achievable level, and a miss is notable rather than routine.
The error budget drives behavior. The team can describe a recent decision, to ship or to slow down, made on the basis of budget remaining.
Indicators reflect user experience. The team can explain how each SLI maps to what users actually feel.
A breach prompts action. When an SLO is missed, the team responds rather than shrugs, because the target was real.
SLOs are reviewed. The team revisits targets and SLIs as the system evolves, rather than leaving them frozen.
Adjacent Capabilities and Connected Work
This work does not exist in isolation. The SLO practice depends on, and feeds into, several adjacent capabilities. Building one without thinking about the others is the most common scoping mistake.
In most enterprise programs, SLOs share infrastructure with the observability stack, the incident management process, and the release pipeline. They share team capacity with SRE, platform engineering, and the product owners who weigh reliability against features. And they share leadership attention with whatever the next reliability initiative is on the roadmap. Naming these adjacencies upfront helps the program scope realistically and helps leadership see the work as a portfolio rather than a one-off project.
The most common mistake in adjacent-capability scoping is treating each adjacency as someone else's problem. The observability that measures the SLIs is your problem. The release process the error budget governs is your problem. The product conversation about reliability-versus-velocity is your problem to inform. Pretending otherwise pushes work to teams that did not plan for it, and the work returns to you later as an ignored SLO or an unresolved velocity debate. Own the adjacencies you depend on; partner with the teams that own them; share the timeline.
Conclusion
An SLO is only useful when the team can hit it and acts on its error budget. The discipline that turns a vanity number into a working tool is the same discipline behind any goal: measure what matters, set a realistic target, and use it to make decisions.
Key Takeaways:
- An SLO you cannot hit is worse than no SLO
- Choose indicators users feel and targets the system can meet
- Make the error budget drive real reliability-versus-velocity decisions
Setting SLOs well requires indicator, target, and operating discipline. When done correctly, it produces:
- Targets the team respects and usually meets
- An error budget that settles the velocity tradeoff with data
- Reliability set where it is actually worth the cost
- A living practice that evolves with the system
What Logiciel Does Here
If your SLOs are aspirational and ignored, choose indicators users feel, set targets the system can hit, and make the error budget drive concrete decisions.
What Logiciel Does Here
If your SLOs are aspirational and ignored, choose indicators users feel, set targets the system can hit, and make the error budget drive concrete decisions.
Learn More Here:
- Incident Management and On-Call Engineering
- The SRE Error Budget Conversation With Product
- Observability-Driven Development: Instrument Before You Ship
At Logiciel Solutions, we work with engineering and platform leaders on SLO design, error budgets, and reliability operating models. Our reference patterns come from production SRE practices.
Explore how to set SLOs your team can actually hit.
Frequently Asked Questions
What is a service level objective?
A target for a measurable indicator of service health, set at a level the system can realistically meet, paired with an error budget, the allowed shortfall, that the team uses to balance reliability against the pace of change.
Why is an unachievable SLO worse than none?
Because an SLO missed every month trains the team to ignore it, eroding the whole practice. A realistic target that is usually met, and acted on when missed, is a tool the team respects and uses.
What is an error budget?
The allowed shortfall implied by an SLO target, for example, the downtime permitted by a 99.9% availability goal. Teams use the remaining budget to decide whether to ship and take risk or to slow down and focus on reliability.
How do I choose a good SLI?
Pick an indicator that reflects what users actually experience, availability, latency, or correctness, measured where the user feels it rather than deep in the stack. An SLI disconnected from experience produces an SLO that can be met while users suffer.
What is the biggest mistake in setting SLOs?
Choosing aspirational targets to look impressive. They get breached routinely and ignored, and chasing unnecessary nines wastes engineering effort. Set targets the system can meet and the use case needs, and make the error budget drive real decisions.
