How to clean up memory on a CentOS virtual machine?

There are several ways to clean up memory in a CentOS virtual machine.

1. By using the “sync” command, you can synchronize data from memory to the disk and free up some memory.
2. Running the free command allows you to view the current usage of memory, including used and available memory. After using the free command, you can determine if you need to clean up memory based on the situation.
3. Executing the command echo 3 > /proc/sys/vm/drop_caches can clear the page cache, directory entries, and inode cache. It is important to note that this operation may cause some performance decline as the system will need to re-cache data.
4. Rebooting the virtual machine: If the above methods are unable to free up enough memory, restarting the virtual machine can be considered, as this will clear the memory and reload the operating system.

Before clearing the memory, make sure you understand the current memory usage and ensure it won’t disrupt any active processes or services. If unsure about terminating a process, back up related data first and test the system stability after clearing the memory.