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.
Why do you need to monitor Linux?
Whether you’re a professional SysAdmin, DevOps, a Linux dev, or just someone who enjoys using it, having the right tools to track your system’s performance is essential. Monitoring allows proactive identification of issues before they snowball into problems impacting users or applications. By tracking resource utilization like CPU, memory, disk space, and network traffic, bottlenecks can be pinpointed and addressed. Like a high-performance engine – with monitoring, you can optimize resource utilization, prevent performance issues, and keep your system running smoothly. Monitoring also aids in troubleshooting. When bugs arise, having historical data on resource usage provides a valuable baseline to pinpoint the root cause.
Benefits of using a Linux monitoring tool
The benefits of Linux monitoring extend beyond performance optimization. It empowers administrators to track system health and availability, especially crucial for environments where downtime is costly. Monitoring tools can alert you to service outages, performance degradation, or even security threats. Timely intervention based on these alerts minimizes downtime and ensures critical services remain up and running. Furthermore, monitoring plays a vital role in security. It keeps a watchful eye on system activity, detecting suspicious behavior or unauthorized access attempts. By monitoring system logs, file integrity, and network traffic, you can identify potential security breaches and take swift action to mitigate risks and protect sensitive data.
Choosing the right Linux monitoring tool
There’s a toolbox available for Linux monitoring, catering to different needs and preferences. Classic command-line tools like top, vmstat, and iostat provide real-time insights into resource usage and system activity, however, for comprehensive monitoring and advanced features, you should acquire a Linux monitoring tool. Imagine a customizable dashboard displaying key metrics, historical data analysis, and alerts for potential issues. These tools integrate with other systems and services, providing a centralized platform for comprehensive system health monitoring. Here’s what to consider when selecting a Linux monitoring tool:
- Scalability: Can the tool handle the growing amount of data your Linux systems generate over time? Consider log volume, server count, and future growth.
- Features: Does it offer the functionalities you need? Look for real-time monitoring, specific metrics (CPU, memory, disk), alerting systems, visualizations and collaboration features
- Alerting: How customizable are the alerts? You’ll want options for defining thresholds, notification methods (email, SMS, etc.), and escalation paths for critical issues.
- Pricing: Does it fit your budget? Look for a solution with overage protection, and with transparent pricing.
- Ease of Use: Is it user-friendly for your team? Look for intuitive interfaces, clear dashboards, and easy-to-understand reports.
- Integrations: Does it integrate with existing tools?
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.
Here is how these 10 Linux monitoring tools compare across the most important features:
1. Sematext
Sematext’s server monitoring tool provides real-time visibility into the performance of your Linux servers.
It collects and reports Linux serves resource utilization and key performance metrics such as CPU, memory, disk usage, processes, network, and load. A really nice feature that is not directly tied to monitoring performance, but that platform engineers, site reliability engineers, and other such folks will appreciate is the Inventory (check docs). Not only can you see the list of all your servers (or VMs or cloud instances, of course) and their specs, but you can also compare them side by side. You think your infra is all uniform?
Ha! You might be surprised that you have multiple Linux distributions, versions, different kernels, different sets of packages installed, etc. – this is the sort of stuff exposed there. If you are running Kubernetes on your Linux boxes, that will get picked up automatically and you’ll see rich out-of-the-box dashboards with everything you can imagine about your deployments. The agent is lightweight and easily installable.
One of our favorite features is automated discovery of services running on the Linux host (or inside containers and Kubernetes pods) as well as logs. These are exposed in the UI, so you can easily pick and choose which servers and which logs you want to monitor.
Pros:
- Really affordable
- Metric correlation between application performance and database traces and log analytics
- Support for integrations with all leading cloud providers, Kubernetes, containers, etc.
- Super simple GUI-based metric and log monitoring setup
- Support for anomaly detection and alerts
- Full-stack observability
Cons:
- Nothing specific to Linux monitoring
- No application transaction tracing yet (coming later this year)
Pricing:
- 14-day free trial without credit card available
- Paid plans start at $2.8 per month per host
2. Zabbix
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.
Pros
- Native Zabbix agent that runs on Linux servers; small footprint; can be extended
- Supports the functionality to automatically discover and register Linux servers with the Zabbix server
- Large and active online community
- Monitors servers, networks, applications, and services with real-time alerts
- Offers plugins and extensions for tailored monitoring solutions
- A free open-source tool with comprehensive features
- Alerting with anomaly detection
- Integrations with third-party tools and APIs
Cons
- Complex initial deployment and configuration setup
- Requires a database server setup to store configurations
- Can consume substantial system resources in large environments
- Lacks some capabilities found in commercial tools
- Documentation sometimes lacks detail and clarity
- UI/UX needs improvements for better usability
- Difficult procedures for backing up and migrating between versions
Pricing
- Free open-source tool. Zabbix also offers different tiers of technical support based on your use case.
3. 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 the *nix kernel and then stores them 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.), and then make them available to the Prometheus server to scrape.
Pros
- 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
- Free and open-source with a huge open-source community for support
- Support for custom metrics; huge number of exporters available to export metrics to Prometheus from different sources
- Integration with multiple data sources and third-party tools
- Comprehensive, and customizable visualizations via Grafana
- Proactive alerting via anomaly detection (Prometheus) and support through various notification channels (Grafana)
Cons
- Complex and time-consuming to manage Prometheus instances; operational overhead if your staff is unfamiliar with the tool
- Need to manually configure and manage Prometheus exporters
- Manual setup required for graphs and alerts
- Steep learning curve
- Some users reported a lack of billing transparency and clarity
- Some users reported that the UI could be improved
- No auto-scaling capabilities
Pricing
- Free and open-source Linux monitoring tools.
4. Nagios XI
Nagios XI, the enterprise evolution of the open-source Nagios Core, offers comprehensive Linux server monitoring with enhanced functionality and reduced administration overhead. It excels at tracking Linux server metrics, application performance, and network traffic through strategically placed monitoring agents.
For Linux environments, Nagios collects data via two primary methods:
- Dedicated agents installed directly on Linux servers and network components
- SNMP queries to network devices for status information
Deployment involves downloading the appropriate Linux package bundle, completing the installation process, and performing initial configuration. Once agents are deployed across your Linux infrastructure, data immediately begins populating the standard dashboards.
Nagios XI particularly shines in Linux environments due to its native compatibility with Unix-based systems. Its highly customizable nature allows for tailored monitoring of specific Linux distributions, services, and performance metrics. This flexibility makes it ideal for enterprises with complex Linux infrastructures.
While the extensive customization options provide powerful monitoring capabilities for Linux servers, they do require additional technical expertise and ongoing maintenance to fully leverage the platform’s potential in Linux environments.
Pros
- 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
- Support for network-related components like routers, switches, and other physical hardware
- Highly customizable; supports custom metrics
- Supports monitoring both Windows and Linux servers
- Active user community
Cons
- Limited set of default dashboards
- Users reported a complex initial setup with a steep learning curve
- Maintenance and operational overhead
- Users reported high licensing cost
Pricing
- Free, open-source version (Nagios Core) available with limited features
- Free trial available for all Nagios products
- Paid plans start at $2,495 for a 100-node license for the standard edition. Enterprise edition is an additional $1,995. Unlimited node license is available for $23,995
5. Elastic Stack
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), and 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.
Pros
- Support for file integrity and Linux audit data monitoring using Auditbeat
- Monitoring of your Linux server network traffic enabled by Packetbeat
- Popular; large community
- Free to use, eliminating licensing fees
- Aggregates logs from cloud environments into a searchable index
- Horizontal scaling handles large data volumes efficiently
- Rapid search responses support real-time analytics
- JSON-based API supports complex data analysis
Cons
- Complex setup; high deployment cost for multiple stack components
- Requires expertise for log parsing and data pipelines
- Resource-intensive; needs substantial computing infrastructure
- Focused on centralized logs management
- Steep learning curve requires training to leverage full capabilities
- Users reported documentation lacking examples
Pricing
- Open-source, free to use. There are commercially hosted options for it, like Sematext Cloud.
- Paid plans start at $95/month
6. Datadog
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.
Pros
- Ability to monitor Linux process trees
- Diagnosing out-of-memory and system errors on Linux
- Ability to detect security threats in systems’ Linux processes
- Support for log aggregation and analytics
- Support for anomaly detection and alerts
- Support for custom metrics
- Over 850 native integrations
- Support for hybrid environments
- Customizable dashboards
- Compliance tracking
- Full-stack observability platform
Cons
- Complex to use; can be overwhelming for new users
- Limited log analytics due to lack of support for JSON log processing
- Expensive pricing. User reports that “Once you got onto Datadog (a closed platform), they will leverage switching cost to squeeze you”
- No overage protection
- Some users reported difficult-to-understand documentation
Pricing
- 14-day free trial available for all solutions
- Free plan available for 1 day retention, up to 5 hosts
- Paid plans start at $18 per month per host for 15 months retention
Want to see how Sematext stacks up? Check out our page on Sematext vs Datadog. Additionally, you should familiarize yourself with all the alternatives to Datadog and how they compare to it.
7. 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.
Pros
- 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
- End-to-end network monitoring
- Monitoring for physical devices, e.g., routers and switches
- Monitors and troubleshoots VoIP performance
- Customizable dashboards and graphs
- Automated workflows for fault resolution
- Security and event log monitoring
Cons
- No cloud-based SaaS version is available
- Application performance monitoring and network correlation are not available
- Operational overhead due to managing continuous patch updates
- Users reported issues with third-party integrations
- Some users reported a limited auto-discovery feature
Pricing
- Free version that lets you monitor up to three devices.
- Paid plans are determined by each customer’s needs. Some sources suggest a starting price of $95/year for 10 devices that scale with the number of devices.
8. 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.
Pros
- 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)
- End-to-end monitoring support with correlated metrics
- Automatic service discovery and application dependency mapping
- Support and recommendations for server capacity planning
- Praised technical support for being responsive and efficient
- Customizable dashboards
Cons
- No anomaly detection for alerts
- No support for identity federation with LDAP
- Generic and limited reporting filters in the dashboard
- Doesn’t provide end-to-end visibility
- Steep pricing for SMBs
- Some users reported configuration difficulties
- Some users reported challenges with scalability and performance in complex setups, making instance management intricate.
- Some users reported that the UI needs improvement
Pricing
- 30-day free trial available
- Paid plans are not publicly available (talk with sales required), but a reseller license starts at a hefty price of +$45,000/year for 200 nodes + 1st-year maintenance
9. Site24x7
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 providing 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.
Pros
- 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
- Monitors CPU, memory, disk, and network statistics
- Intuitive dashboard accessible via mobile and desktop
- Uptime monitoring available
- Customizable alerts & flexible notification configurations based on specific thresholds
- Monitors applications, logs, virtual systems, and network devices
Cons
- Complex manual setup; lack of automation
- Difficult to add custom plugins
- Users reported difficulties with report customization
- Users reported the tool being non-intuitive and difficult to use
Pricing
- “Forever free plan” available
- Paid plans start at $9/month, but to get a somewhat comprehensive feature set, the $35/mo plan is required
Want to see how Sematext stacks up? Check out our page on Sematext vs Site24x7.
10. 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.
Pros
- 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
- Monitors network, server, and application performance from a single platform
- Intuitive and customizable dashboard for various technical levels
- Fast setup with efficient data collection and real-time monitoring
Cons
- On-premises version for Windows only
- Exponential licensing based on the number of sensors
- Users reported scalability issues beyond 10K sensors
Pricing
- 30-day free trial
- Paid plans start at $1,750 per server license for about 500 sensors, or you can purchase perpetual licensing via a one-time payment.
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 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.
Author Bio 
Ehab Qadah 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).