Linux is one of the most popular operating systems today, powering a large portion of the Internet. According to W3Techs, almost half of today’s top-ranked 1 million websites currently run on Linux systems. So, if you want your site—and the application(s) running on it—to be high-performing with lots of uptime, you need to ensure the availability and reliability of your Linux-based servers.
Fortunately, there are tons of great tools and software on the market that can help you effectively monitor the health and performance of your Linux servers. They even allow you to automate alerts so you can respond to issues quickly and minimize the impact on your end users’ experience.
To help you get started, we’ve put together a list of the best paid, free, and open-source Linux monitoring tools currently out there.
Sematext’s server monitoring tool provides real-time visibility into the performance of your Linux servers by showing your current and historical resource utilization and collecting key performance metrics, such as CPU, memory, disk usage, processes, network, and load. Sematext also provides a server inventory software that gives you a unified view of your Linux servers, with information such as kernel version, distribution, hardware details, and installed packages.
The software is based on a lightweight agent. One great feature is automated discovery, which observes your servers and collects metrics. It also offers alert and log reports in a single pane so you can easily identify and optimize poorly performing servers.
- Anomaly detection on any Linux performance metric
- Easy setup and automation support; a hosted service
- Automatic discovery of services running on Linux servers
- Linux process monitoring limited to the top 10 running processes by CPU/memory
- Lack of agent documentation for older Linux versions
Sematext offers a 14-day free trial. There are also three pricing tiers: Basic (free infrastructure monitoring of up to three hosts), Standard ($0.007 per container host/hour), and Pro ($0.011 per container host/hour).
Zabbix provides an open-source monitoring solution for any type of server, network, cloud, application, or database. You can use it to monitor your Linux servers and collect performance metrics including CPU usage, network bandwidth usage, and available disk space.
Zabbix offers out-of-the-box templates with pre-configured metrics, triggers, graphs, applications, screens, and rules that you can view and use on a central Zabbix server. It also allows you to configure triggers based on logical tests for monitored statistics (for example, if the load average is too high, per CPU, on a Linux server). Then you can define an action based on the trigger event to deliver notifications and alerts through e-mail, SMS, script alerts, or webhooks—or let Zabbix fix the problem by executing remote scripts.
- Native Zabbix agent that runs on Linux servers; small footprint; can be extended
- Supports the functionality to automatically discover and register Linux servers with Zabbix server
- Large and active online community
- Complex initial deployment and configuration setup
- Requires a database server setup to store configurations
Zabbix solutions are open source, so you can use them for free. Zabbix also offers different tiers of technical support based on your use case.
3. SolarWinds Server & Application Monitor (SAM)
SolarWinds Server & Application Monitor (SAM) offers automated tools that allow you to track the performance of your applications and Linux servers. It lets you easily view the usage of Linux server resources, such as CPU, memory, disk usage, networking, and processes, so that you can optimize server and application configurations.
SAM uses agent and agentless data-collection mechanisms for remote Linux monitoring. You can monitor system performance to identify issues like high response times and network packet loss or track resource utilization and processes. There are also built-in monitoring templates for applications running on Linux servers, such as Apache Tomcat.
- Automatic discovery of apps and Linux servers
- Out-of-the-box templates for Linux server distributions (Red Hat, CentOS, SUSE, Ubuntu, Debian, Fedora, etc.)
- Analytics tools for understanding monitoring metrics (e.g., insights into anomalies)
- Time-consuming manual environment setup
- High cost; requires an ongoing subscription
SAM offers a free 30-day trial, as well as a subscription plan and perpetual licensing per number of modes. For up to 1,000 nodes, pricing starts at $1,622 for a subscription and $2,995 for a perpetual license.
4. ManageEngine OpManager
ManageEngine OpManager is a great tool that offers network and performance monitoring capabilities for Linux servers, giving you real-time visibility into metrics such as CPU usage, memory usage, disk I/O utilization, server availability, and network traffic. You also get auto-discovery of all services running on these servers, which can help you automatically map availability and response time. Customizable dashboards feature tons of built-in performance widgets to fit your monitoring needs.
ManageEngine OpManager supports most Linux distributions, including Red Hat Linux, Red Hat Enterprise Linux, Mandriva Linux, Fedora, SUSE, Debian, Ubuntu, and CentOS.
- Monitors traffic metrics, such as packet loss, on the Linux network
- Intelligent analytics for Linux server performance trends
- Support for Linux hardware monitoring (e.g., CPU fan speed) and Linux network inventory
- Great for network monitoring, but little support for other Linux server components
- On-premises deployment only
ManageEngine OpManager offers a 30-day free trial. There are two types of licensed versions: subscription (starting at $395) and perpetual (starting at $795).
5. PRTG Network Monitor
PRTG Network Monitor from Paessler is a Linux performance monitoring software that uses sensors to monitor a single metric in your network (e.g., the traffic of a switch port, CPU load, or free drive space). You typically need about 5–10 sensors per Linux server.
This tool monitors all types of Linux servers, offering features like built-in support for customized sensors using WBEM, SSH, and Syslog protocols. For instance, SSH sensors collect metrics like free disk space, load average, and the memory usage of your server. What’s more, PRTG’s dashboard provides an overview of the status and performance of your server and notifies you of issues as they occur.
- No need for modifying or installing anything on the monitored Linux servers (i.e., agentless)
- Out-of-the-box auto-discovery that detects all devices and services in your Linux-based systems
- Configurable and flexible alerts using built-in notifications via e-mail or customized on top of PRTG APIs
- On-premises version for Windows only
- Exponential licensing based on the number of sensors
PRTG offers a 30-day free trial. Prices start at $1,750 per server license for about 500 sensors, or you can purchase perpetual licensing via a one-time payment.
6. Prometheus and Grafana
Prometheus and Grafana are used together as an open-source monitoring and alerting solution with support for Linux servers. Prometheus mainly collects the Linux hardware and OS metrics exposed by *nix kernel and then stores as time-series data, using a pull model over HTTP. You can find metrics information in a multi-dimensional data model of the timestamped metrics (i.e., metrics with their collection times, alongside labels/key-value pairs).
You can easily connect Grafana dashboards for data visualization with your Prometheus server or use pre-built official or community Grafana dashboards for the Prometheus data source.
To monitor Linux server performance, you’ll need to install a node exporter utility that collects multiple hardware-related and kernel-related metrics (CPU, disk utilization, memory, network statistics, etc.), then makes them available to the Prometheus server to scrape.
- Multi-dimensional data model of numeric time-series data; suitable for distributed Linux servers
- Supports automatic service discovery for target Linux servers
- Low infrastructure requirements
- No auto-scaling capabilities
- No built-in dashboard and visualization solution with Prometheus; must set up and use Grafana dashboards too
Prometheus and Grafana are fully open source, so they can be downloaded and used for free.
7. Nagios Core
Nagios Core is an open-source Linux/Unix systems monitoring and alerting tool that can be extended through custom plugins, providing flexible Linux server monitoring. It remotely executes different plugins (executables or scripts) on your Linux server using the NRPE (Nagios Remote Plugin Executor) add-on, which gives you comprehensive monitoring data, including OS metrics, services/processes state, CPU, memory, ping rate, and disk usage. There are a lot of community plugins for different Linux server distributions.
Nagios Core also offers availability and historical reports, and you can configure alerts via e-mail or SMS in case something goes wrong.
- Remediation using event handlers that can automatically restart failed applications or Linux servers
- Supports trending and capacity planning for Linux server upgrades
- Runs natively on Linux systems
- Scalability; no auto-discovery for hosts and services
- Complex manual setup of the NRPE add-on on the monitored Linux server
Nagios Core is open source and free. The paid enterprise solution, Nagios XI, comes in two plans: Standard (starting at $1,995 per 100 nodes) and Enterprise (starting at $1,995 per 100 nodes + $1,500 for the Software Edition).
Site24x7 is a cloud-based monitoring software for websites and infrastructure components, such as Linux servers, applications, networks, and cloud services. You can install its agent on your Linux server to collect more than 60 performance metrics, including load average, CPU, memory, disk, network bandwidth utilization, and recent Linux syslogs.
Site24x7 can monitor the services and processes running on your Linux servers, giving you their CPU and memory usage, and provide visibility on thread counts. Its powerful dashboards let you view all the metrics collected and make instant decisions. You can also configure alerts for when issues arise.
- AI-powered performance Linux monitoring capabilities
- Self-hosted outside the subscriber’s data center
- Supports tracking changes on Linux server’s ports, directories, and Linux syslogs
- Complex manual setup; lack of automation
- Difficult to add custom plugins
Site 24×7 offers a free 30-day trial. After that, you can monitor ten servers for $9 per month, with the option to buy additional instances or different add-ons.
Datadog is a SaaS-based monitoring solution compatible with Linux and Unix systems. On your Linux server, you can install the Datadog agent, which automatically collects standard performance metrics, such as CPU and disk usage, and sends them to your Datadog account. Datadog’s real-time Linux monitoring capabilities allow you to visualize the health and performance of your Linux servers. The tool’s Live Processes view collects information about the process trees running on your Linux server, giving you the data views you need to understand spikes in resource usage caused by certain processes and applications.
Datadog provides interactive dashboards to analyze your monitoring and performance data, and you can set up server automated alerts for performance thresholds, violations, or anomalies. It supports sending notifications via e-mail, Slack, webhooks, and PagerDuty.
- Ability to monitor Linux process trees
- Diagnosing out-of-memory and system errors on Linux
- Ability to detect security threats in systems’ Linux processes
- Steep learning curve for new users
- Overhead of initial setup and installation of agents
Datadog offers a 14-day free trial. There are three pricing tiers: Free (up to five hosts with 1-day metric retention), Pro ($15 per host, per month), and Enterprise ($23 per host, per month).
10. Elastic Stack
Lastly, the Elastic Stack (ELK Stack) is a well-known tool for Linux performance monitoring. It’s composed of Elasticsearch (full-text search), Logstash (a log aggregator), Kibana (visualization via graphs and charts), and Beats (lightweight metrics collectors and shippers).
You can leverage all of ELK Stack’s capabilities to monitor your Linux servers by installing Metricbeat (an Elastic Beat), then configuring it to periodically collect system and service metrics including CPU, memory usage, disk, and network IO statistics. Metricbeat ships them to the rest of the ELK Stack for transformation, visualization, and alerting.
- Support for file integrity and Linux audit data monitoring using Auditbeat
- Monitoring of your Linux server network traffic enabled by Packetbeat
- Popular; large community
- Complex setup; high deployment cost for multiple stack components
- Focused on centralized logs management
ELK is open source, so it’s free to use. There are commercially hosted options for it, like Sematext Cloud.
What Should You Choose to Monitor Linux Performance?
So, after all that, it’s clear that choosing the right Linux server monitoring tool is critical in ensuring the performance and availability of your business applications. Sure, there are a lot of options on the market today, but not all of them will necessarily suit your given use case. When choosing a monitoring software for your Linux system, it’s important to consider various criteria.
Think about the answers to these questions:
- Is the tool easy to use? Is the added overhead and work worth the advantages you’ll gain?
- Can it monitor both servers and applications? Can it monitor applications on your servers or does it treat servers as black boxes?
- Does it support automation workflow (including automatic discovery) or does it require a lot of manual work?
- How customizable is the software? (The best tools allow you to freely customize as needed for your particular use case.)
- If you choose a paid commercial solution, are the costs worth the functionalities you’ll gain?
As we mentioned before, Sematext Server Monitoring ticks all of these boxes. It gives you full visibility into the availability and performance of your servers, along with alerting and reports from a single pane.
Check out our 14-day free trial to discover all the functionalities Sematext has to offer.
Ehab has extensive experience in software engineering and technical leadership roles for over ten years. His main interests involve large-scale back-end development, microservices architecture, cloud infrastructures/DevOps, distributed systems, data engineering, technical writing, and people management. Ehab holds a master’s degree in computer science from the University of Bonn, Germany and he is currently leading the R&D team at Alma Health (UAE-based healthcare startup).