50 lines
1.3 KiB
Markdown
50 lines
1.3 KiB
Markdown
---
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tags:
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- memory
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- disks
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- Linux
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- operating-systems
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---
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# Swap space
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A swap partition is a partition on a disk that is not intended to be used as a
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filesystem. Instead, it is a part of the disk that is used to augment the main
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memory.
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If you run out of memory and have set up a swap partition, the OS will be able
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to move pieces of memory to and from disk storage. This is called _swapping_
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because pieces of idle programs are swapped to the disk in exchange for active
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pieces residing on the disk.
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## View current swap usage
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If you have a swap space established, the command `free` will show current
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usage:
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```bash
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free
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total used free shared buff/cache available
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Mem: 16099420 3031572 10157652 1153144 2910196 11605820
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Swap: 3145724 0 3145724
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```
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## Create a swap partition
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To use an existing disk partition as a swap you can run the command
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`mkswap [device]` and then `swapon [device]` to register the space with the
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[kernel](The_kernel.md).
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### Add to `fstab`
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You will want the swap to be activated every time the OS boots so add the
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following line to the [fstab](Filesystems.md#fstab),
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where `/sda3` is used as the example partition:
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```bash
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/dev/sda3e none swap sw 0 0
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```
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## Create a swap file
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// Add info here
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