Swap memory is a portion of the hard disk (HDD or SSD) space which is reserved and made available for use by the operating system when the main memory (RAM) utilization reaches high.

When memory demand increases and the available memory is less, inactive pages in the RAM is moved to swap space and thereby releasing resource in the main memory. Though hard disk supports RAM for immediate memory demand, it cannot be considered as an alternative to RAM because of the slow input output operation capability in hard disk.

This article describes about how to check the utilization of swap memory space in our system.

OS Information : Debian GNU/Linux 9

The FREE command

Free command is used to display memory free and used memory.

Parameter “-h” displays size in nearest possible 3 digit format.


free -h


The TOP command

This command is used to view the running processes in the system.

The header section displays the swap memory utilization




The VMSTAT command

This command shows information about virtual memory statistics




/proc/swaps file

This command shows swap file and device name


cat /proc/swaps


This commands helps the administrators monitor the swap memory utilization.

Thank you for reading the article. Hope this is helpful to you.