In Linux, swap space is used when the system runs out of physical memory (RAM). Swap memory is usually a “set it and forget it” type of affair, but sometimes it needs to be cleared to improve system performance. If your system is using swap a lot, it will affect the overall performance of the system, as traditional drives are much slower than RAM.
To clear swap space in Linux, you can cycle off the swap using the
swapoff command. This moves all data from swap memory back into RAM. However, before doing this, you need to be sure that you have enough RAM to support this operation. You can check what is being used in swap and in RAM by running the
free -h command.
If you want to delete Linux swap, you can edit the
/etc/fstab file and delete the entry for the swap file. If the swap space is a file, you can simply remove it. Or, if the swap space is on a separate slice and you are sure you will not need it again, you can make a new file system and mount the file system.
To free up memory on Linux, you can clear the cache using the
sync command and the
drop_caches file in the
/proc/sys/vm/ directory. You can clear the PageCache only, dentries and inodes, or all three by running the respective commands:
echo 1 > /proc/sys/vm/drop_caches,
echo 2 > /proc/sys/vm/drop_caches, or
echo 3 > /proc/sys/vm/drop_caches.
It is important to note that clearing the cache can improve the performance of your system, but it can also slow it down temporarily as the system rebuilds the cache. Additionally, you should be cautious when managing swap space, as it can have a significant impact on the performance of your Linux system.
Frequently Asked Questions
How to Clear Swap Memory on Ubuntu?
To clear swap memory on Ubuntu, you can use the “swapoff” command to disable swap and then use the “swapon” command to enable it again. First, check the amount of swap used/available using the “free -m” command. Then, disable swap using the “sudo swapoff -a” command. Wait for approximately 30 seconds for the swap space to clear, and then enable swap using the “sudo swapon -a” command.
How Do I Check Which Process is Using Swap Memory in Linux?
To check which process is using swap memory in Linux, you can use the “smem” command. The “smem” command reports memory usage with shared memory divided proportionally across processes that share that memory. To see the swap usage by process, use the “smem -t -m” command.
How to Clear Swap Memory on CentOS 7?
To clear swap memory on CentOS 7, you can use the “swapoff” command to disable swap and then use the “swapon” command to enable it again. First, check the amount of swap used/available using the “free -m” command. Then, disable swap using the “sudo swapoff -a” command. Wait for approximately 30 seconds for the swap space to clear, and then enable swap using the “sudo swapon -a” command.
How Do I Check the Amount of Swap Memory in Linux?
To check the amount of swap memory in Linux, you can use the “free” command. The “free” command shows the total amount of physical and swap memory in the system, as well as the amount of memory used and free.
How to Increase Swap Memory in Linux?
To increase swap memory in Linux, you can create a swap file or a swap partition. To create a swap file, use the “fallocate” command to create a file of the desired size, format it as swap using the “mkswap” command, and then enable it using the “swapon” command. To create a swap partition, use a partitioning tool such as “fdisk” or “parted” to create a new partition, format it as swap using the “mkswap” command, and then enable it using the “swapon” command.
What is Swap Memory in Linux and How Does it Work?
Swap memory in Linux is a portion of the hard disk that is used as virtual memory when the physical memory (RAM) is full. When the system runs out of physical memory, it moves some of the data from the RAM to the swap space to free up memory for other processes. Swap memory is slower than physical memory, so excessive swapping can slow down the system.