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How to Choose the Best Linux Distro for Your Email Server

An email server is a mission-critical system that needs to provide always-on availability and great performance. The Linux distribution (distro) powering the email server plays a pivotal role in meeting these expectations while also ensuring ease of management and tight security.

This comprehensive 2500+ word guide will elaborate on the nuances between distributions and help organizations pick the perfect Linux distro for hosting their email workloads.

Evaluating the Key Criteria

The suitability of a Linux distro for managing enterprise email infrastructure depends on how well it measures up on the following aspects:

High Availability and Reliability

The distro must deliver outstanding uptime and ensure continuity of email services should hardware or software problems arise, through features like live patching, high availability clustering, fault tolerance capabilities etc.


Robust security is a prerequisite through capabilities like advanced firewall management, sophisticated authentication mechanisms, latest encryption, containment solutions like SELinux and AppArmor etc.

Performance and Scalability

A distro must combine efficient resource utilization and performance tuning features to handle growing email volumes and users. Auto-scaling, elastic computing and load distribution capabilities add to such future-proofing.


Easy administration through intuitive dashboards, process automation and configuration management simplifies email infrastructure operations. Tight integration with popular clients like Outlook or Thunderbird should also be provided out-of-the-box.

Support and Interoperability

Commercial or community support options for the OS as well as interoperability with related infrastructure components like monitoring, backup, identity management etc. greatly minimize management overheads.

We will now assess the most popular Linux distros on the above parameters to identify strengths and weaknesses of each option.

In-Depth Comparison Between Distributions

Linux distributions take different approaches towards balancing the myriad capabilities expected from a high-performance and resilient email server platform. Let‘s analyze how the various offerings stand out.

Ubuntu Server


Ubuntu Server leverages Debian‘s strong foundations and enriches it further for data center workloads. Its intuitive dashboards, wizards and automation capabilities simplify management tasks. Long Term Support (LTS) releases provide extended stability and version lifecycles.

High Availability

From automated load balancing to live kernel patching to reduce downtimes, Ubuntu offers extensive high availability features. The pace of new HA capability additions is faster than more conservative enterprise distros.


Universal security controls like AppArmor and firewall along with rapid updates put Ubuntu Server at par with RHEL or SUSE when it comes to security. Additional hardening scripts and tools further lock down deployments.

Performance and Scalability

The optimized Linux kernel provides excellent computational speeds for email and web servers while background processes get prioritized scheduling. Auto-scaling and orchestration for horizontal scale-out deployments further aid with right-sizing email infrastructure.


From Phone and Desktop integration to LDAP identity management, Ubuntu offers smooth end user experience. System dashboards provide easy instrumentation while Puppet & Ansible aid automation at scale.

Support and Licensing

While community resources and documentation are extensive, commercial 24×7 enterprise-grade support is only available via Canonical‘s paid Ubuntu Advantage program unlike RHEL or SUSE with included support subscriptions.

Red Hat Enterprise Linux (RHEL)


RHEL prioritizes stability, security and certification compliance above all else. For risk-averse enterprises running business-critical applications like email on Linux, RHEL provides the reassurance needed.

High Availability

Clustering, failover configurations & advanced backup mechanisms make RHEL deployments resilient to outages. Load redistribution post incidents is automatically handled to minimize performance impact.


SELinux policies, advanced authentication mechanisms like two-factor authentication and encryption safeguard RHEL‘s email infrastructure. Security Content Automation Protocol (SCAP) capabilities further harden environments and facilitate compliance.

Performance and Scalability

Optimized for scalability right from compile flags to the kernel to file system choices, RHEL delivers excellent speeds for memory, network and disk intensive workloads. Performance Co-Pilot (PCP) and tunable parameters further optimize configurations.


For CLI-savvy Linux admins, RHEL‘s management capabilities via Puppet, Ansible and Cockpit web console are unmatched. Interoperability with monitoring, identity and infrastructure tools is a key selling point.

Support and Licensing

Included premium support subscriptions make mission-critical workload deployments less daunting for enterprises. Long 10-year support lifecycles require less frequent version upgrades as well. But these benefits and more controlling change management come for a subscription cost that grows with scale.

SUSE Linux Enterprise Server


SUSE creates Linux distro specifically tailored for mission-critical workloads. The platform is hardened from ground up for security, reliability and certification compliance necessary for large enterprises.

High Availability

SUSE offers comprehensive server clustering, transparent failover and live patching capabilities for maximizing email infrastructure resiliency and uptime. Near continuous operations even during minor incidents or maintenance is a key strength.


AppArmor for application containment, sophisticated authentication mechanisms and encryption protocols allow SUSE Linux to meet stringent enterprise security needs. Integrated data protection further secures email communications.

Performance and Scalability

Right sized resource allocation, parallelized workflows and NUMA optimizations provide speed and scale. Performance tuning parameters can be adjusted to optimize for email server metrics like mailbox operations, SMTP transactions per minute etc.


SUSE Manager provides single pane of glass for server deployment and configuration management tasks. Tight integration with Microsoft environments for identity, clients and backups eases management for enterprises with mixed data centers.

Support and Licensing

Being enterprise-focused, SUSE comes with premium 24×7 support for business-critical infrastructure. But the subcription cost, like RHEL, makes it an expensive proposition for smaller organizations.

Key Considerations for Picking the Right Linux Distro

With a myriad of capable Linux distros available to choose from, organizations need to carefully assess which platform aligns best with their business environment. Let‘s look at some scenarios and the ideal distro match for each one:

Cost Sensitive Small Business

For growth stage companies with 5-50 employees, email costs and overhead need to be contained without compromising too much on features. Ubuntu Server or CentOS Stream allow maximizing capabilities while keeping licensing costs in check even as scale grows.

Mid-size Organization Seeking Reliability

Mature companies with 50-500 employees are likely to prefer platform stability and continuity of operations. Red Hat Enterprise Linux, with its focus on resilient deployments and included premium support, fits such needs well.

Large Enterprise with Stringent Compliance Needs

Heavily regulated multinational corporations need capabilities like advanced security controls, extensive auditing mechanisms and strict access policies. SUSE Linux Enterprise Server or Red Hat Enterprise Linux help fulfill these requirements.

Managed Service Provider Seeking Centralized Management

MSPs need to keep operating overheads low by managing multiple customer installations efficiently. Ubuntu Server‘s dashboards and orchestration along with DevOps-friendly capabilities help consolidate management.

Media Agency Handling Large File Attachments

For organizations dealing with multimedia content, fast and uninterrupted email throughput is key. SUSE Enterprise Linux‘s performance tuned configurations and failover handling are well aligned for such needs.

Optimizing Linux for Email Server Performance

Choosing the right Linux distro provides only the foundation for building a high performance and resilient email infrastructure. Additional operating system and infrastructure layer optimizations are vital as well:

  • Configure Dedicated Partitions: Providing separate disk partitions with appropriate block size, throughput limits and file system types is crucial for optimal database and log IO handling by mail storage.

  • Enable Swap Space: Configuring adequate swap space allows heavy workloads generated at peak times to execute smoothly preventing server chokes. Swappiness tuning further optimizes this.

  • Tune System File Handles: Databases and log analytics that are part of email infrastructure generate lots of open file handles. Increasing limits through ulimit, inotify etc. helps avoid hindrances.

  • Disable Unnecessary Services: Pruning activities unrelated to mail server like print or desktop services reduces boot times, attack surfaces and optimizes hardware resource allocation for email.

  • Implement Monitoring: Integrating OS and application monitoring provides visibility into capacity usage trends. It allows planning upgrades and troubleshooting accurately.

  • Automate Patching: Scheduling regular OS and service pack updates along with automated testing and rollback mechanisms minimizes disruptions while keeping environments secure.

  • Harden Access Controls: Enforcing complex passwords, scrubbing default accounts, enabling multi-factor authentication for admins rather than just passwords protects environments.

  • Setup Load Balancing: Distributing user authenticate and mailbox traffic helps in sustainably handling growth at scale. Global load balancers add redundancy against regional outages.

Carefully architecting and managing infrastructure around the distro allows extracting the most business value from Linux investments.


With email being among the most business critical application within organizations, the Linux OS underpinning the server plays an indispensable role. Beyond evaluating technical capabilities, understanding long term supportability, ease of operations and costs is crucial while making a distro selection.

Red Hat Enterprise Linux and SUSE Linux Enterprise Server provide hardened reliability apt for large deployments but come with premium licensing fees. Ubuntu Server balances usability and customization with a reasonable total cost of ownership. Workload isolation, dedicated compute and regular testing / drills around high availability complete the picture.

Equipped with perspectives on strengths of different distributions, their applicability by organization profile and pointers on optimizing deployments, IT teams can now make judicious Linux investments delivering higher email server ROI.