Overview
swapon activates a specified swap partition or swap file by adding it to the system's virtual memory space. This helps the system cope with low RAM situations and maintain overall stability.
Key Features
- Activate swap partitions or files
- Activate all swap spaces defined in /etc/fstab
- Display information about currently active swap spaces
- Set the priority of swap spaces
Key Options
Commonly used options with the swapon command.
Activation and Information Display
Advanced Settings
Generated command:
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Description:
`swapon` Executes the command.
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Usage Examples
Various examples of managing swap space using the swapon command.
Activate a Specific Swap Partition
sudo swapon /dev/sdb2Activates the /dev/sdb2 partition as swap space.
Activate a Specific Swap File
sudo swapon /swapfileActivates the file at /swapfile as swap space.
Activate All Swap Defined in /etc/fstab
sudo swapon -aUsed to manually activate swap spaces that are set to be automatically activated at system boot.
Check Information of Currently Active Swap Devices
swapon --showDisplays detailed information about the swap spaces currently active on the system in a table format.
Summary of Swap Space Usage
swapon -sDisplays a summary of the total size, used space, and free space of active swap spaces.
Tips & Precautions
Useful tips and precautions when using the swapon command.
Swap Space Management Tips
- Swap spaces must be formatted with the `mkswap` command before they can be activated.
- To use swap space permanently, its information must be added to the `/etc/fstab` file.
- Use the `swapoff` command to deactivate swap spaces.
- When creating a swap file, create the file using the `dd` command, format it with `mkswap`, and then activate it with `swapon`.
Precautions
- Permissions: The swapon command modifies system settings, so root privileges are required (use sudo).
- Performance Impact: Swap space is on the hard disk and is much slower than RAM. Excessive swap usage can lead to system performance degradation.
- File System: Swap files are created on top of regular file systems. If the underlying file system is corrupted, the swap file can also be affected.