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<!DOCTYPE html>
<html lang="en">
<head>
<!-- Google tag (gtag.js) -->
<script async src="https://www.googletagmanager.com/gtag/js?id=G-J0S6RM2D7G"></script>
<script>
window.dataLayer = window.dataLayer || [];
function gtag(){dataLayer.push(arguments);}
gtag('js', new Date());gtag('config', 'G-J0S6RM2D7G');
</script>
<meta charset="UTF-8">
<meta name="theme-color" content="#FFBC52">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<link rel="stylesheet" href="index.css">
<meta name="description" content="A simple Service Level Calculator that complies with Google SRE books.">
<meta property="og:title" content="Service Level Calculator">
<meta property="og:description" content="A simple Service Level Calculator that complies with Google SRE books.">
<meta property="og:image" content="https://slc.alexewerlof.com/img/icon.png">
<meta property="og:url" content="https://slc.alexewerlof.com">
<meta property="og:type" content="website">
<link rel="icon" type="image/svg" href="img/icon.svg">
<link rel="manifest" href="manifest.json">
<title>Service Level Calculator</title>
</head>
<body>
<noscript>
<p>This web application requires JavaScript to work.</p>
</noscript>
<main id="app" v-cloak>
<header>
<transition>
<div class="announcement" v-if="showAnnouncement">
<ext-link href="https://blog.alexewerlof.com/p/slc">Read the announcement about this app</ext-link>.
<button @click="showAnnouncement = false" type="button">Dismiss</button>
</div>
</transition>
<a href="/">
<h1>
<img src="img/icon.svg" alt="Service Level Calculator Logo" class="logo" />
Service Level Calculator
</h1>
</a>
<ul class="top-nav only-mobile">
<li><a href="#sli-title">SLI</a></li>
<li><a href="#slo-title">SLO</a></li>
<li><a href="#error-budget-title">Error Budget</a></li>
<li><a href="#alert-title">Alerting</a></li>
<li><a href="#share-title">Share</a></li>
</ul>
</header>
<article>
<!------------------------ SLI ------------------------>
<section>
<h1 id="sli-title">
SLI
<help-component>
<p>
In simple words <ext-link href="https://blog.alexewerlof.com/p/sli">Service Level Indicators
</ext-link> are the metrics that represent how the reliability
is perceived by the consumers of the service. They are normalized to be a number between
0 and 100 using this formula:
</p>
<math>
<mrow>
<mi>SLI</mi>
<mo>=</mo>
<mfrac>
<mrow>
<mi>Good</mi>
</mrow>
<mrow>
<mi>Valid</mi>
</mrow>
</mfrac>
<mrow>
<mo>×</mo>
<mn>100</mn>
</mrow>
</mrow>
</math>
<p>
You can read more about the definition of
<ext-link href="https://blog.alexewerlof.com/p/sli-good">Good</ext-link>
and
<ext-link href="https://blog.alexewerlof.com/p/valid-vs-total">Valid</ext-link>
.
</p>
<p>
Common SLIs include latency, availability, yield, durability, correctness, etc.
</p>
</help-component>
</h1>
🎉Tip: <ext-link href="templates/index.html">Use Templates</ext-link>
<h3>
<label for="sli-title-input">Title</label>
</h3>
<input id="sli-title-input" type="text" v-model="title" :placeholder="config.title.placeholder">
<h3>
<label for="sli-description-input">Description</label>
</h3>
<textarea
id="sli-description-input"
rows="2"
type="text"
v-model="description"
:placeholder="config.description.placeholder"></textarea>
<h2>
Type
<help-component>
<p>
SLIs can either be either:
<ul>
<li>
<em>Time-Based</em>: Concerned with the <em>duration</em> of good time in a given period.
The duration is actually a time window where the data is aggregated for a good/bad result.
In a sense the Time-Based SLI is also an Event-Based SLI where an event is an
aggregation window.
</li>
<li>
<em>Event-Based</em>: Concerned with the <em>count</em> of good events in a set of valid events in a given time period.
</li>
</ul>
Learn more
<ext-link href="https://blog.alexewerlof.com/p/time-based-vs-event-based">
here
</ext-link>.
</p>
</help-component>
</h2>
<div class="block">
<p>
<label>
<input
type="radio"
v-model="isTimeBased"
:value="false">
Event-Based
</label>
</p>
<p>
<label>
<input
type="radio"
v-model="isTimeBased"
:value="true">
Time-Based
</label>
</p>
</div>
<div v-if="isTimeBased">
<!-- SLI Time Slot -->
<h3>
<label for="sli-event-unit">Event Unit: {{ sloWindow.normUnit }}</label>
<help-component>
<p>
The time slot is the time window that the metric data is aggregated to
calculate a good/bad time period.
</p>
<p>
For example, probing an endpoint every 60 seconds to see if it is available,
assumes that the endpoint is available for the entire 60 seconds.
</p>
<p>
Another example is percentiles. When calculating the 99th percentile of the
latency every 5 minutes, the aggregation window is 5 x 60 = 300 seconds.
</p>
<table>
<caption>Typical time slot lengths</caption>
<thead>
<tr>
<th>Time Slot</th>
<th>Seconds</th>
<th aria-label="try button"></th>
</tr>
</thead>
<tbody>
<tr v-for="p in config.timeSlot.presets">
<td>{{ p.title }}</td>
<td>{{ p.seconds }}</td>
<td><button type="button" @click="unit = p.seconds">Try!</button></td>
</tr>
</tbody>
</table>
</help-component>
</h3>
<input
id="sli-event-unit"
type="range"
:min="config.timeSlot.min"
:max="config.timeSlot.max"
:step="config.timeSlot.step"
placeholder="60"
v-model.number="unit">
</div>
<div v-else>
<!-- SLI Event Unit -->
<h3>
<label for="sli-event-unit">Events Unit</label>
<help-component>
<p>
The unit of the event that the SLI is measuring.
This is mainly used in the UI to make it easier to understand.
</p>
<p>
If the Good and Valid events are the same type, you can use a
custom event name. Otherwise, you can just use the default
and generic "event".
</p>
<table>
<caption>Common event units</caption>
<thead>
<th>Event Unit</th>
<th>Use case</th>
<th aria-label="try button"></th>
</thead>
<tbody>
<tr v-for="p of config.unit.presets">
<td>{{ p.unit }}</td>
<td>{{ p.useCase }}</td>
<td><button type="button" @click="unit = p.unit">Try!</button></td>
</tr>
</tbody>
</table>
</help-component>
</h3>
<input
id="sli-event-unit"
type="text"
v-model="unit">
</div>
<!-- SLI: Good -->
<h2>
<label for="sli-good-input">Good {{ sloWindow.normUnit }}</label>
<help-component>
<p>
<ext-link href="https://blog.alexewerlof.com/p/sli-good">
What are good {{ sloWindow.normUnit }}
</ext-link>
from consumer's perspective?
How do good {{ sloWindow.normUnit }} look like?
What is the metric that you can measure to identify the
good {{ sloWindow.normUnit }} from all the valid {{ sloWindow.normUnit }}?
</p>
</help-component>
</h2>
<input
id="sli-good-input"
type="text"
v-model="good">
<!-- SLI: Valid -->
<div class="block">
<h2>
<label for="sli-valid-input">
Valid {{ sloWindow.normUnit }}
</label>
<help-component>
<p>
<ext-link href="https://blog.alexewerlof.com/p/sli-good">
What are the {{ sloWindow.normUnit }}
</ext-link>
that are important to the service consumer?
You probably don't want to count all the {{ sloWindow.normUnit }}.
This is an opportunity to narrow down the scope of the optimization
and what triggers an alert.
</p>
<p>
For simplicity, sometimes "total" is used instead of "valid".
But
<ext-link href="https://blog.alexewerlof.com/p/valid-vs-total">
there is a difference
</ext-link>.
</p>
<p>
While
<ext-link href="https://blog.alexewerlof.com/p/sli">
Service level indicator
</ext-link>
guides the optimization,
the definition of valid scopes that optimization for two reasons:
<ul>
<li>Focus the optimization effort</li>
<li>Clarify responsibility and control</li>
</ul>
</p>
<p>
Leave this field empty to use "total" instead.
</p>
</help-component>
</h2>
<input
id="sli-valid-input"
type="text"
v-model="valid"
>
</div>
<!-- Service Level Formula -->
<h2>
Service Level Formula
<help-component>
<p>
The formula for calculating SLI for the given SLO window is
the percentage of good per valid.
</p>
<p>
Depending on whether the SLI is
<ext-link href="https://blog.alexewerlof.com/p/time-based-vs-event-based">time-based or event-based</ext-link>,
the formula calculates the percentage of bad time or bad events.
</p>
<math>
<mrow>
<mi>SLI</mi>
<mo>=</mo>
<mfrac>
<mrow>
<mi>Good {{ sloWindow.normUnit }}</mi>
</mrow>
<mrow>
<mi>Valid {{ sloWindow.normUnit }}</mi>
</mrow>
</mfrac>
<mrow>
<mo>×</mo>
<mn>100</mn>
</mrow>
</mrow>
</math>
</help-component>
</h2>
<div class="code block">
<div class="formula" id="sli-formula-code">
<div class="formula__fraction">
<div class="formula__fraction--top">
<code>
<span class="funct">count</span>
<span class="punct">(</span>
<label for="sli-event-unit">
<span class="exprs">{{ sloWindow.normUnit }}</span>
</label>
<span class="punct">, </span>
<label for="sli-good-input">
<span class="exprs">{{ good }}</span>
</label>
<span class="punct">)</span>
</code>
<span class="invis"> /</span>
</div>
<div class="formula__fraction--bottom">
<code>
<span class="funct">count</span>
<span class="punct">(</span>
<label for="sli-event-unit">
<span class="exprs">{{ sloWindow.normUnit }}</span>
</label>
<span v-if="valid" class="punct">, </span>
<label v-if="valid" for="sli-valid-input">
<span class="exprs">{{ valid }}</span>
</label>
<span class="punct">)</span>
</code>
</div>
</div>
<div class="formula__whole">
<code>
<span class="punct"> × </span>
<span class="const">100</span>
</code>
</div>
</div>
<button @click="copy('sli-formula-code', 'sli-formula')" type="button" title="Copy to clipboard">⎘</button>
</div>
</section>
<!------------------------ SLO ------------------------>
<section>
<h1 id="slo-title">
<label for="slo-int-input">
SLO: {{ percL10n(slo) }}
</label>
<help-component>
<p>
Service Level Objective (SLO) is the target percentage of good {{ sloWindow.normUnit }}.
</p>
<p>
Using the two sliders below you can fine tune the SLO to your needs.
The first slider is for the integer part of the percentage ({{ percL10n(sloInt) }}).
The second slider is for the fractional part of the percentage ({{ percL10n(sloFrac) }}).
</p>
<table>
<caption>Typical SLO values</caption>
<thead>
<tr>
<th>Informal Name</th>
<th>SLO Value</th>
<th aria-label="try button"></th>
</tr>
</thead>
<tbody>
<tr v-for="p in config.slo.presets">
<td>{{ p.title }}</td>
<td>{{percL10n(p.slo)}}</td>
<td><button type="button" @click="slo = p.slo">Try!</button></td>
</tr>
</tbody>
</table>
</help-component>
</h1>
<div v-if="slo > 99.9" class="info block">
<p>
Note: Just be mindful of the price tag for this high service level <em>objective</em>!
</p>
<p>
Everyone wants the highest possible number but
<ext-link href="https://blog.alexewerlof.com/p/10x9">
not everyone is willing to pay the price.
</ext-link>
</p>
</div>
<div v-if="slo < 70" class="info block">
<p>
Note: this is an unusually low service level objective.
Typically service level <em>objective</em> is above {{ percL10n(90) }} with some rare exceptions.
Please check the <a href="#error-budget-title">Error budget</a> for implications of your chosen SLO.
</p>
</div>
<input
id="slo-int-input"
type="range"
:min="config.slo.min"
max="99"
v-model.number="sloInt"
>
<h3>
<label for="slo-frac-input">Fraction: {{ percL10n(sloFrac) }}</label>
<help-component>
<p>
This slider allows fine tuning the SLO.
It is mostly for convenience when deciding a reasonable error budget
while keeping an eye on it.
</p>
<table>
<thead>
<tr>
<th>{{ sloInt }}.XYZ</th>
<th>Subtract</th>
<th>Add</th>
</tr>
</thead>
<tbody>
<tr>
<th>X</th>
<td><button type="button" @click="changeSLO(-0.1)">{{ percL10n(-0.1) }}</button></td>
<td><button type="button" @click="changeSLO(0.1)">{{ percL10n(+0.1) }}</button></td>
</tr>
<tr>
<th>Y</th>
<td><button type="button" @click="changeSLO(-0.01)">{{ percL10n(-0.01) }}</button></td>
<td><button type="button" @click="changeSLO(0.01)">{{ percL10n(+0.01) }}</button></td>
</tr>
<tr>
<th>Z</th>
<td><button type="button" @click="changeSLO(-0.001)">{{ percL10n(-0.001) }}</button></td>
<td><button type="button" @click="changeSLO(0.001)">{{ percL10n(+0.001) }}</button></td>
</tr>
<tr>
<th>XYZ</th>
<td colspan="2"><button type="button" @click="sloFrac = 0">reset</button></td>
</tr>
</tbody>
</table>
</help-component>
</h3>
<input
id="slo-frac-input"
type="range"
min="0"
max="0.999"
step="0.001"
v-model.number="sloFrac"
>
<!-- SLO Window -->
<h2>
<label for="slo-window-unit-multiplier">
Window:
{{ windowDays }} days
</label>
<help-component>
<p>
The SLO window (also known as the
<ext-link href="https://blog.alexewerlof.com/p/compliance-period">compliance period</ext-link>)
is the time period
for which the SLO is calculated.
</p>
<p>
Essentially this adjusts the <em>forgiveness</em> of the SLO.
For example if the window is 30 days, we are not concerned with any incidents
and breaches of SLO that happened before that.
</p>
<p>
Smaller windows also help prevent the error budget from accumulating too much.
For example, if the SLO is 99% for a time-based Availability SLI (uptime),
the error budget allows 432 minutes of downtime per month.
This amount can be consumed in multiple down times during the month or one chunk of long downtime.
But the same SLO allows only 100 minutes of downtime per week.
</p>
<p>
It is usually 30 days or 4 weeks.
</p>
<p>
You can play with different ranges to see how a given SLO translates to different
good {{ sloWindow.normUnit }} and how it impacts the error budget.
</p>
<table>
<caption>Typical compliance periods</caption>
<thead>
<tr>
<th>Window</th>
<th>Days</th>
<th>Advantage</th>
<th aria-label="try button"></th>
</tr>
</thead>
<tbody>
<tr v-for="p of config.windowDays.presets">
<td>{{ p.title }}</td>
<td>{{ p.days }}</td>
<td>{{ p.useCase }}</td>
<td><button type="button" @click="windowDays=p.days">Try!</button></td>
</tr>
</tbody>
</table>
</help-component>
</h2>
<p>
{{ sloWindow }}
</p>
<input
type="range"
:min="config.windowDays.min"
:max="config.windowDays.max"
:step="config.windowDays.step"
v-model.number="windowDays"
id="slo-window-unit-multiplier"
>
<!------------------------ Error budget ------------------------>
<h1 id="error-budget-title">
Error budget: {{ percL10n(errorBudgetPerc) }}
<help-component>
<p>
Error budget is one of the core ideas behind using SLI/SLOs to improve reliability.
Instead of denying or forbidding errors, error budget allows the system to fail
within a pre-defined limit.
</p>
<p>
The number one enemy of reliability is change.
But we need change to be able to improve the system.
Error budgets do exactly that.
They provide a budget of error for the team to improve the system while keeping
the consumers happy enough.
</p>
<p>
Error budget is the complement of SLO.
It is the percentage of bad {{ sloWindow.normUnit }} that you can have
before you violate the SLO.
</p>
<math>
<mtable>
<mtr>
<mtd>
<mi>error_budget</mi>
</mtd>
<mtd>
<mo>=</mo>
<mn>100</mn>
<mo>-</mo>
<mi>SLO</mi>
</mtd>
</mtr>
<mtr>
<mtd></mtd>
<mtd>
<mo>=</mo>
<mn>{{ percL10n(100) }}</mn>
<mo>-</mo>
<mi>{{ percL10n(slo) }}</mi>
<mo>=</mo>
<mn>{{ percL10n(errorBudgetPerc) }}</mn>
</mtd>
</mtr>
</mtable>
</math>
<table>
<thead>
<tr>
<th></th>
<th>Subtract</th>
<th>Add</th>
</tr>
</thead>
<tbody>
<tr>
<th>{{ numL10n(1) }}</th>
<td><button type="button" @click="changeErrorBudget(-1)">{{ numL10n(-1) }}</button></td>
<td><button type="button" @click="changeErrorBudget(1)">{{ numL10n(1) }}</button></td>
</tr>
<tr>
<th>{{ numL10n(10) }}</th>
<td><button type="button" @click="changeErrorBudget(-10)">{{ numL10n(-10) }}</button></td>
<td><button type="button" @click="changeErrorBudget(10)">{{ numL10n(10) }}</button></td>
</tr>
<tr>
<th>{{ numL10n(100) }}</th>
<td><button type="button" @click="changeErrorBudget(-100)">{{ numL10n(-100) }}</button></td>
<td><button type="button" @click="changeErrorBudget(100)">{{ numL10n(100) }}</button></td>
</tr>
<tr>
<th>{{ numL10n(1000) }}</th>
<td><button type="button" @click="changeErrorBudget(-1000)">{{ numL10n(-1000) }}</button></td>
<td><button type="button" @click="changeErrorBudget(1000)">{{ numL10n(1000) }}</button></td>
</tr>
<tr>
<th>{{ numL10n(10000) }}</th>
<td><button type="button" @click="changeErrorBudget(-10000)">{{ numL10n(-10000) }}</button></td>
<td><button type="button" @click="changeErrorBudget(10000)">{{ numL10n(10000) }}</button></td>
</tr>
</tbody>
</table>
</help-component>
</h1>
<div class="warning block" v-if="errorBudget.eventCount === 0" aria-colcount="warning block">
<p>
Warning: The error budget is 0 based on the number of valids {{ sloWindow.normUnit }}.
</p>
</div>
<error-budget-component
:error-budget="errorBudget"
:error-budget-perc="errorBudgetPerc"
:good-event-count="goodEventCount"
:valid-event-count="validEventCount">
</error-budget-component>
<div v-if="!isTimeBased">
<h3>
<label for="error-budget-example-input">Expected number of valid {{ sloWindow.normUnit }}</label>
<help-component>
Here you can enter the numbers for your expected load and see
how many {{ sloWindow.normUnit }} are allowed to fail during the SLO window
while still being within the error budget.
</help-component>
</h3>
<p>
<label for="sli-valid-input">
<code>{{ valid }}</code>
</label> <label for="sli-event-unit">
<code>{{ sloWindow.normUnit }}</code>
</label>
in
<label for="slo-window-unit-multiplier">
{{ sloWindow.humanTime }}
</label>:
</p>
<input
type="number"
v-model.number="estimatedValidEvents"
id="error-budget-example-input"
:min="config.estimatedValidEvents.min"
:max="config.estimatedValidEvents.max"
:step="config.estimatedValidEvents.step">
</div>
<h3>
<label for="bad-event-cost-input">Average cost of bad</label> <label for="sli-event-unit"><code>{{ sloWindow.normUnit }}</code></label>
<help-component>
<p>
When one of the
<label for="sli-event-unit">
<code>{{ sloWindow.normUnit }}</code>
</label>
violates the
<label for="sli-good-input">
<code>{{ good }}</code>
</label>
condition,
how much does it cost the business or your team?
</p>
<p>
This cost will be used to put a tangible number on various windows and events.
It might be hard to put a number on failures especially if some resilience patterns are part of the architecture.
</p>
<p>
There are many ways to make the failures cheaper.
In a future article, we will discuss all patterns of reliability and how to make errors cheap.
In the mean time check out the following techniques:
</p>
<ul>
<li>
<ext-link href="https://blog.alexewerlof.com/p/fallback">Fallback</ext-link>
</li>
<li>
<ext-link href="https://blog.alexewerlof.com/p/failover">Failover</ext-link>
</li>
</ul>
</help-component>
</h3>
<input type="number"
id="bad-event-cost-input"
v-model.number="badEventCost"
:min="config.badEventCost.min"
:max="config.badEventCost.max"
:step="config.badEventCost.step">
<h4>
<label for="bad-event-currency-input">Currency</label>
<help-component>
<p>
You can set the currency to see how much it costs to violate the SLO.
If you can't put a currency on the errors, feel free to get creative.
</p>
<table>
<caption>Typical Currencies</caption>
<tr>
<th>Abbreviation</th>
<th>Description</th>
<th></th>
</tr>
<tr v-for="p of config.badEventCurrency.presets">
<td>{{ p.currency }}</td>
<td>{{ p.description }}</td>
<td><button type="button" @click="badEventCurrency = p.currency">Try!</button></td>
</table>
</help-component>
</h4>
<input
id="bad-event-currency-input"
type="text"
v-model="badEventCurrency">
</section>
<!------------------------ Alert ------------------------>
<section>
<h1 id="alert-title">
Alerting
<help-component>
<p>
What is the point of setting SLI/SLO if we are not going to take application
when the SLO is violated?
</p>
<p>
Alerting on error budgets enable us to be on top of the reliability of our system.
When using service levels, the alert triggers on the rate of consuming the error budget.
</p>
<p>
When setting an alert, the burn rate decides how quickly the alert reacts
to errors.
</p>
<ul>
<li>
Too fast and it will lead to false positives (alerting unnecessarily)
and alert fatigue (too many alerts).
</li>
<li>
Too slow and the error burget will be burned before you know it.
</li>
</ul>
<p>
Google SRE Workbook goes through
<ext-link href="https://sre.google/workbook/alerting-on-slos/">
6 alerting strategies based on SLOs
</ext-link>.
</p>
</help-component>
</h1>
<!-- Error Budget Burn Rate -->
<h2>
<label for="burn-rate-input">
Burn rate: {{ burnRate }}x
</label>
<help-component>
<p>
Burn rate is the rate at which the error budget is consumed.
It is the ratio of the error budget to the SLO window.
</p>
<p>
A burn rate of <button @click="burnRate = 1">1x</button> means that the error budget will be consumed during the
SLO window (accepted).
</p>
<p>
A burn rate of <button @click="burnRate = 2">2x</button> means that the error budget will be consumed in half the
SLO window. This is not acceptable because at this rate, the SLO will be
violated before the end of the SLO window.
</p>
<p>
Google SRE Workbook goes through 6 alerting strategies and
<ext-link href="https://sre.google/workbook/alerting-on-slos/">
recommends
</ext-link>:
</p>
<table>
<thead>
<th>Burn Rate</th>
<th>Error Budget</th>
<th>Long-Window</th>
<th v-if="shortWindowVisible">Short-Window</th>
<th>Action</th>
<th aria-label="try button"></th>
</thead>
<tbody>
<tr>
<td>14.4x</td>
<td>{{ percL10n(2) }} Consumed</td>
<td>1 hour</td>
<td v-if="shortWindowVisible">5 minutes</td>
<td>Page</td>
<td>
<button type="button" @click="burnRate = 14.4, longWindowPerc = 2, shortWindowDivider = 12">
Try!
</button>
</td>
</tr>
<tr>
<td>6x</td>
<td>{{ percL10n(5) }} Consumed</td>
<td>6 hours</td>
<td v-if="shortWindowVisible">30 minutes</td>
<td>Page</td>
<td>
<button type="button" @click="burnRate = 6, longWindowPerc = 5, shortWindowDivider = 12">
Try!
</button>
</td>
</tr>
<tr>
<td>1x</td>
<td>{{ percL10n(10) }} Consumed</td>
<td>3 days</td>
<td v-if="shortWindowVisible">6 hours</td>
<td>Ticket</td>
<td>
<button type="button" @click="burnRate = 1, longWindowPerc = 10, shortWindowDivider = 12">
Try!
</button>
</td>
</tr>
</tbody>
</table>
<p>
Note: The above values for Long-Window and Short-Window are based on a 1-month SLO window.
You can see your actual values in the comments below Long-Window and Short-Window.
</p>
</help-component>
</h2>
<input
id="burn-rate-input"
type="range"
:min="config.burnRate.min"
:max="config.burnRate.max"
:step="config.burnRate.step"
v-model.number="burnRate"
>
<!-- Burn Chart Component -->
<burn-rate-component
:burn-rate="burnRate"
:error-budget-burn="errorBudgetBurn"
:slo-window-budget-burn="sloWindowBudgetBurn">
</burn-rate-component>
<!-- Long Window Alert -->
<h2>
Long-Window
<help-component>
Long-window alert is the "normal" alert.
The reason it is called "long" is to distinguish it from the "short-window"
alert which is primarily used to reduce false positives and improve the alert reset time.
</help-component>
</h2>
<!-- Alert after consuming -->
<h3>
<label for="alert-error-budget-perc">
After Consuming ≥ {{ percL10n(longWindowPerc) }}
</label>
<help-component>
<p>
We don't want to wait for the entire error budget to be consumed before
alerting! It will be too late to take action.
</p>
<p>
Therefore the alert should trigger before a significant portion of the
error budget is consumed.
</p>
<p>
Based on your setup, the alert will trigger after we have consumed
{{ percL10n(longWindowPerc) }} of the entire time allotted for the error budget
(or SLO compliance window) which is
<time>{{ sloWindow.humanTime }}</time>.
</p>
<math>
<mrow>
<mi>TTTrigger</mi>
<mo>=</mo>
<mn class="const">{{ percL10n(longWindowPerc) }}</mn>
<mo class="funct">×</mo>
<mn class="const">{{ sloWindow.humanSec }}</mn>
<mo class="punct">=</mo>
<mn class="const">{{ alertLongWindow.humanSec }}</mn>
</mrow>
</math>
<p>
Assuming that the entire error budget was available at the begining of the incident,
the maximum time available to respond before the entire error budget is exhausted is:
</p>
<p>
Because:
</p>
<math>
<mrow>
<msub>
<mi>TTRespond</mi>
<ms>max</ms>
</msub>
<mo>=</mo>
<mn>{{ errorBudgetBurn.humanSec }}</mn>
<mo>-</mo>
<mn>{{ alertLongWindow.humanSec }}</mn>
<mo>=</mo>
<mn>{{ alertTTRWindow.humanSec }}</mn>
</mrow>
</math>
<p>
Which is
<time>{{ alertTTRWindow.humanTime }}</time>.
</p>
<p>
Remember that this is the best case scenario.
In reality, you may have much less time if you don't want to consume the entire error budget for an incident.
Also note that the burn rate can be higher than {{ burnRate }}x.
</p>
</help-component>
</h3>
<div v-if="alertLongWindow.sec < 600" class="warning block">
<p>
Warning: The alert is too "jumpy" as in: it will trigger too often.
This may lead to alert fatigue or even worse: ignoring the alerts.
</p>
</div>
<div v-if="alertTTRWindow.sec < 3600" class="info block">
<p>
Note: The time to resolve (TTR) is too short for a human to react.
It is strongly recommended to automate the incident resolution instead of relying on human response to alerts.
</p>
</div>
<div v-if="longWindowPerc > 33" class="warning block">
<p>
Warning: Remember that the alert will trigger after consuming {{ percL10n(longWindowPerc) }} of the error budget is consumed! That error budget is for {{ sloWindow.humanTime }}.
</p>
<p>
Based on your setting an alert burns {{ percL10n(longWindowPerc) }} just to trigger. Then it needs some time to resolve too.
</p>
<p>
How many alerts like this can you have in {{ sloWindow.humanTime }} before the
entire error budget is consumed?
</p>
</div>
<input
id="alert-error-budget-perc"
type="range"
:min="config.longWindowPerc.min"
:max="config.longWindowPerc.max"
:step="config.longWindowPerc.step"
v-model.number="longWindowPerc"
>
<div v-if="alertLongWindow.sec <= 60" class="warning block">
<p>
Warning: Long alert Window is too short at this burn rate ({{ burnRate }}x)
which may lead to alert fatigue.
</p>
</div>
<div class="error block" v-if="alertLongWindow.eventCount === 0" class="error block">
<p>
Error: Division by zero! Long alert Window is too short for enough valid {{ sloWindow.normUnit }} to be counted.
</p>
</div>
<!-- Burn Chart Component -->