Clear RAM Memory Cache, Buffer and Swap Space on Linux
Like any other operating system, GNU/Linux has implemented memory management efficiently and even more than that. But if any process is eating away your memory and you want to clear it, Linux provides a way to flush or clear ram cache.
How to Clear Cache in Linux?
Every Linux System has three options to clear cache without interrupting any processes or services.
As the root user:
- Clear PageCache only.
sync; echo 1 > /proc/sys/vm/drop_caches |
- Clear dentries and inodes.
sync; echo 2 > /proc/sys/vm/drop_caches |
- Clear pagecache, dentries, and inodes.
sync; echo 3 > /proc/sys/vm/drop_caches |
Explanation of the above command
sync will flush the file system buffer.
Command Separated by ; run sequentially.
The shell waits for each command to terminate before executing the next command in the sequence.
As mentioned in the kernel documentation, writing to drop_cache will clean cache without killing any application/service, command echo is doing the job of writing to file.
If you have to clear the disk cache, the first command is safest in enterprise and production as ...echo 1 >... will clear the PageCache only.
It is not recommended to use the third option above ...echo 3 >... in production until you know what you are doing, as it will clear pagecache, dentries, and inodes.
How to Clear Swap Space in Linux?
If you want to clear Swap space, you may like to run the below command.
swapoff -a && swapon -a |