Swappiness in Linux is a kernel parameter that determines how aggressively the system moves pages from physical RAM to swap space on disk. It’s a value ranging from 0 to 100 in most distributions (some references cite 0–200, but 0–100 is most common). The default value is usually 60.
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Lower swappiness (closer to 0): The system avoids swapping, preferring to keep data in RAM as much as possible.
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Higher swappiness (closer to 100): The system swaps out inactive processes more readily, freeing up RAM for active tasks but potentially increasing disk I/O and latency.phoenixnap+2
Checking the Swappiness Value
You can check the current swappiness value using:
cat /proc/sys/vm/swappiness
or
sysctl vm.swappiness
Changing the Swappiness Value
- Temporarily (does not persist after reboot):
sudo sysctl vm.swappiness=10
- Persistently (survives reboot):
Edit /etc/sysctl.conf and add or change the line:
vm.swappiness = 10
Then, reboot or reload sysctl settings.
Best Practices
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For general desktops, the default value (60) is usually fine.
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For database servers or workloads sensitive to swapping, a lower value (5–10, or even 1) is recommended to reduce the risk of performance degradation due to excessive swapping.ibm+2
Swappiness tuning can help optimize the balance between RAM and swap space usage depending on your workload and hardware configuration.