Long periods of system operation often reveal problems that short tests cannot find. Issues like memory leaks, resource exhaustion, slow performance, and system instability usually appear only after a system has been running continuously for many hours or days.
Soak testing is a very important part of performance testing that helps find these long-term problems.
Soak testing checks how a system behaves when it runs under a steady or heavy load for a long time. It shows whether the system remains stable, fast, and reliable — or slowly starts breaking.
In this article, we will explain soak testing in very simple words. We will cover:
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What is soak testing
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When to perform soak testing
- What problems does it finds
- Key components of soak testing
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How to design a soak test
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How to analyze results
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Benefits of soak testing
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Challenges and solutions
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Real-world examples
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Why is soak testing no longer optional
What is Soak Testing?
Soak testing checks how software performs when it is used continuously for a long time.
Unlike load testing or stress testing, which run for short periods, soak testing runs for many hours, days, or even weeks.
The main goal is simple:
Find problems that only appear after long usage.
These problems include:
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Memory leaks
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Database connection leaks
- File handle leaks
- Slow response over time
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System crashes after long runs
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Resource exhaustion
A soak test should ideally run as long as the system is expected to run in real life.
For example:
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A banking system may run 24/7
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A cloud platform may never stop
- An e-commerce site runs continuously
So the test should reflect that reality.
Real Scenarios Where Soak Testing Helps
Bank Closure Scenario
When a bank announces closure, users rush to withdraw or transfer money. The system suddenly handles heavy transactions continuously.
Even if this situation is rare, the system must survive it.
Soak testing helps verify that the system can handle such unusual long-duration loads without failing.
No On-Call Workers Scenario
Some systems must run over weekends without support staff.
If a system crashes on Sunday night, business losses increase.
Soak testing checks whether the system can run safely for long periods without human support.
When Should You Conduct Soak Testing?
Soak testing is not random. It must be planned properly.
Here are the best times to run soak testing:
Before Release
Before launching a new version, soak testing checks whether the application remains stable during long usage.
It helps prevent production failures.
After Major Changes
Whenever you change:
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Operating system
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Database
- Hardware
- Cloud infrastructure
You must run soak testing again to confirm stability.
During Expected Peak Usage
Before festivals, sales campaigns, or product launches, soak testing ensures the system can handle a long continuous load.
During the Performance Testing Phase
Soak testing should be part of performance testing, after functional testing.
First, confirm that the features work.
Then confirm they work for long periods.
During Off-Peak Hours
Soak tests take a long time. Running them during weekends or nights avoids disturbing real users.
Common Issues Found by Soak Testing
Soak testing finds issues that short tests miss.
Memory Leaks
Memory leaks happen when the system does not release unused memory.
Over time:
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Memory fills
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System slows
- Crashes happen
Soak testing clearly shows this by tracking memory usage continuously.
Database Resource Problems
Problems like:
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Open connections, not closed
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Cursors not released
- Locks not freed
These slowly destroy system stability.
Soak testing reveals them over time.
Performance Degradation
At first, the system is fast.
After many hours:
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Response becomes slow
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Pages load late
- Requests queue up
Soak testing identifies this slow decline.
Key Components of Soak Testing
Soak testing is successful only when planned correctly.
Test Environment
The environment must be very close to production.
Same:
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Servers
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Databases
- Network
- Software versions
Otherwise, the results are not reliable.
Test Scenarios and Workload
Scenarios must match real usage.
For example, in e-commerce:
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Browsing
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Searching
- Adding to cart
- Checkout
Also test across platforms:
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Web
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Mobile web
- App
This ensures full journey coverage.
Monitoring Tools
You must monitor:
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CPU
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Memory
- Disk
- Network
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Threads
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Connections
Without monitoring, soak testing is useless.
Duration
Soak tests are usually run:
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8 hours
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24 hours
- 72 hours
- 1 week
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Or longer
Longer tests find deeper issues.
Resource Utilization
You must study trends.
Not just current usage, but how usage grows.
System Recovery
Test what happens when:
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Server restarts
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Services stop
- Network breaks
The System should recover smoothly.
Real Data
Use realistic production-like data.
Fake small data gives fake results.
Analysis and Reporting
After test:
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Collect graphs
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Compare trends
- Write clear reports
This helps business and technical teams understand risks.
How to Design a Soak Test
Now let’s design a soak test step by step.
1. Define Objectives
Decide what you want to find:
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Memory leaks
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CPU spikes
- DB issues
- Slow performance
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Stability
2. Identify Key Metrics
Track:
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CPU
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Memory
- Disk
- Network
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Response time
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Error rate
3. Create Realistic Scenarios
Understand how users behave.
Create scripts that follow real user paths.
4. Setup Environment
Make the test environment similar to production.
5. Add Monitoring Tools
Use tools like:
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Grafana
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Prometheus
- New Relic
They help see problems clearly.
6. Decide Test Duration
Select duration based on business need.
Critical systems need longer tests.
7. Execute Test
Run scripts continuously.
Monitor all metrics.
8. Analyze Results
Check:
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Slow growth
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Sudden drops
- Resource rise
9. Report Findings
Create reports with graphs and an explanation.
10. Fix and Optimize
Developers fix issues.
11. Re-Test
Test again to confirm fixes worked.
Analyzing Soak Test Results
Proper analysis is very important.
Steps:
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Collect continuous data
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Find trends
- Compare with baseline
- Match with system logs
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Detect leaks
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Review errors
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Prepare reports
This shows the long-term health of the system.
Benefits of Soak Testing
Soak testing provides many business and technical benefits.
Finds Long-Term Problems
Short tests cannot find slow problems. Soak testing can.
Finds Memory Leaks
This is one of its biggest benefits.
Improves Resource Usage
Helps optimize CPU, memory, disk, and network.
Improves User Experience
Users enjoy stable and fast systems.
Confirms Reliability
Systems running 24/7 must be reliable.
Reduces Production Failures
Fix problems before customers see them.
Common Soak Testing Challenges and Solutions
Resource Limitations
- Solution: Use cloud resources and test critical parts first.
Long Test Time
- Solution: Automate monitoring and reporting.
Large Data Volume
- Solution: Use visualization dashboards.
Hard to Find Root Cause
- Solution: Use logs, traces, and break tests into smaller parts.
Hard to Understand Results
- Solution: Use trend analysis and expert review.
Real-World Soak Testing Examples
E-commerce
Testing checkout and payment for weeks before sales.
Streaming Platforms
Testing continuous streaming by millions of users.
Banks
Testing transaction systems during salary days.
Cloud Providers
Testing storage, compute, and network stability.
Gaming
Testing servers for millions of players.
Conclusion: Why Soak Testing Is No Longer Optional
Industry data clearly proves the importance of soak testing:
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78% production failures appear after long usage
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42% crashes are due to memory leaks
- Soak-tested apps have 55% fewer performance problems
- Companies gain 30–40% higher uptime
This shows one thing clearly:
Soak testing is not optional anymore.
In today’s digital world, systems must run continuously.
Even a small slowdown can cause:
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Customer loss
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Revenue loss
- Brand damage
Soak testing ensures:
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Long-term reliability
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Stable user experience
- Lower maintenance cost
- Business safety
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Customer trust
Without soak testing, software may look perfect in short tests but fail in real life.
Final Question
Is your application truly ready for long-term real-world usage?
Do not wait for problems in production.
Partner with Sparkle Web to ensure your software stays stable, scalable, and secure over time. Contact us today.
Sumit Patil
A highly skilled Quality Analyst Developer. Committed to delivering efficient, high-quality solutions by simplifying complex projects with technical expertise and innovative thinking.
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