How to Effectively Clear RAM Cache, Buffers, and Swap Space on Linux

5 Steps To Boost Linux Performance Default view

Linux systems are known for efficiently managing memory, but over time, too much use can cause slower performance. If you are operating a VPS on Voxfor, managing memory consumption is critical to keeping your website fast and Accelerated. Whether you’ve installed new software or left your system running for a long life, your RAM cache, buffer, and swap space can become filled with unused data. Regular clearing helps refresh your server, boosting performance, particularly after tasks like video editing, Big Data Operations, or high-traffic web hosting.

In this guide, you’ll learn how to clear the RAM cache, buffer, and swap space on Linux. It covers commands, technology, and tools like PuTTY to boost system performance. As a Voxfor user, you can easily follow these steps to optimize your Linux VPS or WordPress hosting environment for better performance, whether managing extensive server traffic or preparing your system for heavy file downloads and high-definition video playback. In this guide, you’ll find essential advice to help you optimize your Linux system for operations and tasks.

What Are RAM Caches, Buffers, and Swap Space?

Before jumping into the steps, let us quickly explain these critical components of memory management: 

• RAM Cache: Think of this as quick-access storage. It temporarily stores commonly used data for faster access. However, when the cache is filled with too much data, it can slow down your server performance.
• Buffer: Like a waiting room, the buffer holds data between different system components, ensuring clear communication between the CPU, Memory, and Storage. Too much data in the buffer can slow your server.
• Swap Space: This is a reserve zone on your hard drive. When your RAM is total, inactive processes are moved to the swap space. However, since hard drives are much slower than RAM, using less swap space can cause performance limitations.

Types of Data Stored in RAM cache, Buffer Usage, and Swap Management

• Hosting a WordPress Website: A VPS with many media files (images, videos), the server regularly caches data in RAM to serve content quickly to visitors. If you have heavy traffic or users access a lot of media, the cache can fill up with old content, resulting in slower performance.
• Hosting E-commerce Website: If your VPS runs an e-commerce site that highly updates product data, such as stock or price, the system caches this data for faster access. Over time, uniquely if the data changes often, the cache may become overloaded with old data, slowing down operations such as loading product pages, etc

Benefits of clearing RAM cache, Buffer, and Swap Space

Here are some key reasons why you might want to clear your system memory:

1. Improve performance after installing new software.
2. free up memory after closing large, resource-heavy tasks.
3. prepare your system for running new, memory-consuming applications.
4. Make servers better at managing many tasks at the same time.
5. secure better performance for tasks like system updates or data analysis.
6. event memory issues on high-demand servers.
7. I prove response times on servers that handle client requests.

When Should You Clear the Cache and Swap Space?

While Linux manages memory well, there are times when clearing cache and swap space can increase the speed of your linux servers:

• The server has been online for a very long time.
• The server has executed some resource-consuming tasks.
• The server is slow due to low available memory.

Clearing RAM Cache in Linux: Detailed Commands

Depending on what you need to clear, there are three ways to clear the RAM cache in Linux: PageCache, entries, and inodes. These methods help us clean memory without terminating running applications but should be used carefully on production servers.

Clearing PageCache Using SSH

PageCache is a vital memory management tool in Linux that allows faster access to the system’s information. The system stores cached copies of data from files stored on disk in RAM.

To clear only the PageCache, run the below command in the SSH terminal:

sudo sync; echo 1 > /proc/sys/vm/drop_caches

sync: this clears cached files, helping free up memory, but doesn’t impact important data.

echo 1 > /proc/sys/vm/drop_caches: Clears the PageCache, which stores file-backed memory.

This command is safe to use as it only cleans cached file data, and the active processes run normally.

Clearing Dentries and Inodes

Dentries (directory entries) are data structures the Linux kernel uses to store information about directories and files. They are part of the entry cache, which speeds up file system operations.

An inode is a data structure used to store metadata about a file or directory.

If you need to clear entries (directory cache) and inodes (file metadata):

sudo sync; echo 2 > /proc/sys/vm/drop_caches

echo 2 > /proc/sys/vm/drop_caches: this clears metadata related to files and directories, freeing up space used by them.

This command will free up memory linked with directory and file structure metadata, which can improve performance if your system is under load from file operations.

Clearing PageCache, Dentries, and Inodes at the Same Time

You can clear PageCache, Dentries, and Inodes one at a time or all of them simultaneously.

If you need to clear PageCache, dentries, and inodes all at once, use the following command:

sudo sync; echo 3 > /proc/sys/vm/drop_caches

echo 3 > /proc/sys/vm/drop_caches: Joins both actions, clearing the PageCache, dentries, and inodes simultaneously. T frees the maximum amount of memory.

How to Clear Swap Space in Linux

Swap space in Linux is an extension of RAM, which provides virtual memory that helps maintain the system’s performance and stability. If your server uses too much swap space, you can clear it to improve performance. Clearing swap space becomes beneficial when swap usage increases due to insufficient RAM.

Disable Swap Space:

To turn off and clear swap space:

sudo swapoff -a

• swapoff -a: It is a valuable tool for managing system resources, particularly swap space. It allows you to turn off all active swap partitions and files, successfully allowing the system to remove swap space. The system will instantly turn off all swap partitions and files. T allows the system to claim free space to provide additional memory capacity.

Enable Swap Space Again:

sudo swapon -a

• swapon -a: Re-enables all swap partitions; it allows you to re-enable all active swap partitions and files, successfully allowing the system to use swap space again as needed. The system will activate all previously disabled swap partitions and files. T allows the system to utilize swap space for storing data that doesn’t fit in RAM, providing additional memory capacity.

Clearing swap space can help us improve server performance in the short term, but it is only necessary if your server runs low on memory.

Is It Safe to Clear RAM Cache, Buffer, and Swap Space in Linux?

Generally, Linux is good at managing its resources, including RAM cache, buffer, and swap space. The kernel automatically optimizes memory usage for caching and swapping. However, there are specific scenarios in which clearing these resources is valuable, such as when assigned to high memory pressure or when running a resource-hungry operation. In such situations, clearing the cache, buffer, and swap space can improve the system’s overall performance.

Risks to Consider

• In Production Servers: Manually clearing the cache or buffer during critical operations can cause slowdowns as the server will need to reload data into memory from the start, which may temporarily slow performance.
• Swap Usage: Clearing swap space when memory is deficient can cause the system to become unstable or crash.

We should not clear cache, buffer, and swap often; we should only do so when necessary.

Automating Memory Management with Cron Jobs

If you constantly need to clear cache and swap space, you can automate the process using cron jobs. Cron jobs allow the system to automatically remove cache, buffer, and swap after a set time. This is useful for remote servers that you access via SSH.

Setting Up a Cron Job Using PuTTY

To create a cron job that clears memory at midnight daily, log into your server via PuTTY and edit the crontab file:

crontab -e

Next, add the following lines to clear the cache, buffer, and swap space daily at midnight:

0 0 * * * sudo sync; echo 3 > /proc/sys/vm/drop_caches 0
0 * * * sudo echo 1 > /proc/sys/vm/drop_caches
0 0 * * * sudo sync; echo 2 > /proc/sys/vm/drop_caches 0
0 * * * sudo swapoff -a && sudo swapon -a

Automating this task will free up memory daily, ensuring your server continues to operate efficiently without manual involvement.

Risks of Clearing Cache and Swap Space

While clearing cache and swap can be helpful, there are some risks to be aware of:

• Performance Drops: Clearing the cache too often can slow down your system. When you clear the cache, the system must reload data from the disk, which is much slower than accessing it from the cache. Instead of clearing the cache too often, try to balance keeping it updated and avoiding unnecessary reloading.
• Swap Clearing Risks: Disabling swap space can be risky if your computer doesn’t have enough RAM. It can make your computer run slowly or even crash. It’s best to leave swap enabled unless you have a lot of RAM.

Best Practices

• Only clear memory when needed (e.g., after heavy application or high memory usage).
• For production servers, schedule memory clearing during low-traffic hours to avoid potential downtime.

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Conclusion

On Linux servers, RAM cache, buffer, and swap space need to be regularly maintained, and in the case of sites or apps that use a lot of memory. This guide lets you quickly clear out unused memory in minutes, keeping your system in tip-top shape. Whether you are using a Monthly or a Lifetime VPS on Voxfor Lifetime, these techniques will help to improve your server speed, minimizing the risk of memory-related delays. Consider automating these tasks using cron jobs and optimizing your server memory for consistent and high-performance VPS hosting.

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About Author

Vinayak Baranwal wrote this article. Use the provided link to connect with Vinayak on LinkedIn for more insightful content or collaboration opportunities.