Check

Processes by Swap Space Usage

for file in /proc/*/status

do

  awk '/VmSwap|Name/{printf $2 " " $3}END{ print ""}' $file

done | sort -k 2 -n -r | less

Swappiness

The "swappiness" of a system determines whether the Linux kernel runs with a preference for reclaiming  file pages or anonymous pages. 

• Setting swappiness to 100 gives file pages and anonymous pages equal priority. 

• Reducing the swappiness value tells the OS to bias away from anonymous page reclamation. 

• The default swappiness setting is 60. 

• Setting the swappiness value to zero simply shifts the swap-associated hard drive activity to file-associated hard drive activity (this might be valid if your filesystem disks are significantly more performant than your swap space disks, but this really is a situation you should avoid).

• For single-purpose servers, such as database servers, you may get guidance from the vendor.

You can check the swappiness of your system using...

cat /proc/sys/vm/swappiness 

To change the value to, for example, 30...

sudo sysctl vm.swappiness=30

To make the change persistent over a reboot you need to edit the config file...

/etc/sysctl.conf

Add or update a line like this...

vm.swappiness=30

Clearing Swap

Linux

Assuming that used memory plus used swap space is less that the total memory in your system...

swapoff -a 

wait 30 seconds...

swapon -a 

Adding Swap

Linux

Adding Swap Partition

Assumes a disk device called /dev/myswap has been created...

sudo mkswap -f /dev/myswap

sudo swapon /dev/myswap

Add this line to the bottom of /etc/fstab...

/dev/myswap      swap        swap    defaults        0 0

Adding Swap File

To add a 4GB swap file (instead of using a swap partition)...

sudo dd if=/dev/zero of=/var/myswap bs=1M count=4096

sudo mkswap /var/myswap

sudo swapon /var/myswap

Add this line to the bottom of /etc/fstab...

/var/myswap    swap        swap    defaults        0 0

Bibliography