Check Swap Space Usage on Linux Server
vmstat -s
Look at the used “used swap” metric.
Check if you have a swapfile:
cat /proc/swaps
If you are not using swap space then these commands should show no results.
Set up a Swap File on your Linux Server
If you have less than 2GB of memory then allocate twice the memory amount to the swap file.
cd /var touch swapfile chmod 600 swapfile ls -la swapfile
Use “dd” command to fill the swap file with 1 GB size (as an example) as follows:
dd if=/dev/zero of=/var/swapfile bs=1024k count=1000
Set up the swap file
mkswap /var/swapfile
Enable the Swap File:
swapon /var/swapfile
check if it has been successfully created:
cat /proc/swaps swapon -show
Edit /etc/fstabs to ensure the swap file is enabled each time you boot.
Add the following line to this file:
/var/swapfile none swap sw 00
Test Linux Memory Usage and that the Swap File is Working
Use the program stress, installable from the repositories with
sudo apt-get install stress
To test your RAM use stress -m x where x is the number of workers which will fill up the ram. Choose more workers to use more RAM.
example:
stress -m 5
then look at memory usage with
vmstat -s
or
free -m