Ubuntu Memory Monitoring Guide: How to Check and Optimize RAM Usage on Linux

1. The Importance of Memory Monitoring in Ubuntu

1.1 The Role of Memory Management in Ubuntu

Memory monitoring is a crucial task in Linux systems such as Ubuntu. Checking memory usage is essential for optimizing system performance and allocating resources efficiently. In environments like servers or workloads with high demands, running out of memory can degrade system performance and, in the worst case, cause the system to crash.

Ubuntu provides various tools that make memory monitoring simple and efficient. The following sections explain how to use these tools in detail.

2. How to Check Memory Usage in Ubuntu

2.1 Checking Memory Usage with the free Command

The free command is one of the most common methods to view memory usage in Ubuntu. It allows you to check total memory, available memory, and memory consumed by buffers and cache.

free -h

The -h option displays the output in a human-readable format (GB or MB). The output includes the following fields:

• Mem: Total memory, used memory, and available memory
• Swap: Usage of virtual memory
• Cache: Memory used for buffers and cache

This lightweight command provides quick access to real-time memory information without stressing the system, making it ideal for frequent use.

2.2 Visual Memory Monitoring with the htop Command

The htop command provides real-time, visual monitoring of system resources. Through its graphical interface, htop allows users to intuitively view memory usage for each process.

sudo apt install htop
htop

Once launched, htop displays running processes, their memory usage, CPU usage, and swap consumption. You can also sort or terminate processes with ease. Thanks to its user-friendly, GUI-like interface, it is preferred by many users.

2.3 Checking Memory with the top Command

The top command is used for real-time monitoring of system resource usage. Although it operates in a text-based interface compared to htop, it remains a useful, low-overhead monitoring tool.

top

To sort processes by memory usage, press Shift + M. This helps identify memory-intensive processes when system performance is degraded due to insufficient memory.

2.4 Using /proc/meminfo for Detailed Memory Information

For more detailed memory statistics, you can directly reference the /proc/meminfo file. This file contains memory information managed by the kernel and can be viewed using the cat command.

cat /proc/meminfo

This provides detailed text-based information about total memory usage, cache, and swap space. It offers more granular data compared to free or top, making it useful for advanced memory diagnostics.

3. How to Handle High Memory Usage

3.1 Identifying and Terminating Unnecessary Processes

When memory is running low, the first step is to identify processes consuming excessive memory and terminate them if necessary. Use top or htop to inspect memory usage and stop unnecessary processes.

kill [ProcessID]

The Process ID (PID) can be found in the output of top or htop.

3.2 Managing Swap Memory

In Ubuntu, virtual memory (swap space) is used when physical memory is insufficient. If swap space is running low, you can create additional swap areas.

Steps to Create Swap Space:

sudo fallocate -l 1G /swapfile
sudo chmod 600 /swapfile
sudo mkswap /swapfile
sudo swapon /swapfile

This creates additional swap space, effectively expanding the available memory resources for your system.

4. Conclusion

Monitoring memory in Ubuntu is essential for maintaining system stability. By using tools like free and htop, you can efficiently monitor performance and manage memory usage. Additionally, leveraging swap space and cleaning up unnecessary processes can help optimize resource allocation and ensure a smooth operating environment.