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This article is about how to modify the swappiness value in CentOS7. The editor thinks it is very practical, so I share it with you. I hope you can get something after reading this article.

Example: change the swappiness value to 0

Permanent configuration method:

Sysctl-w vm.swappiness=0

Echo vm.swappiness = 0 > > / etc/sysctl.conf

Temporary configuration method:

Sysctl-w vm.swappiness=0

Manually change the roomy.swappiness value corresponding to the subdirectory under / sys/fs/cgroup/memory

Description of the failure that may occur after temporary configuration:

There is still enough physical memory. Vm.swappiness has been set to 0, but the system still uses swap partitions.

Cause of failure

The root cause is that virtual machine machine.slice and system system.slices, user.slices and so on use swap space.

Direct cause

Setting vm.swappiness through sysctl-w does not change the corresponding values in machine.slice, system.slices, user.slices and so on in cgroup. These values inherit the value of vm.swappiness under / sys/fs/cgroup/memory. When a subdirectory is created, a subdirectory is created, and then the value of vm.swappiness is inherited from the corresponding vm.swappinessvalue in the parent directory. Therefore, when the system is running, only the value of / sys/fs/cgroup/memory is changed in the root directory. The vm.swappiness configuration of the created subdirectories is not affected, so if you need to change it, you have to do it manually.

Summary

Normally, if the value of vm.swappiness is configured in sysctl.conf, all configurations will be new after reboot, but if you change it manually dynamically, you need to manually change the value of roomy.swappiness in the subdirectory under / sys/fs/cgroup/memory.

The above is how to modify the swappiness value in CentOS7. The editor believes that there are some knowledge points that we may see or use in our daily work. I hope you can learn more from this article. For more details, please follow the industry information channel.

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