High Availability Architecture

HA designs for Moodle: fault tolerance, load balancing, redundancy, and operational continuity.

Objective

Keep Moodle available even in the face of infrastructure failures, demand peaks, or scheduled maintenance, without compromising the experience of students and teachers.

Key Components

1. Balancing and Web Layer

Load Balancer (L4/L7): Intelligent distribution and health checks.
Horizontal scaling: Multiple web nodes (Nginx/Apache + PHP-FPM).
Sticky sessions (when applicable): Controlled, avoiding unnecessary coupling.

2. Data and Persistence

Replicated DB: Primary/secondary or cluster depending on criticality.
Verified backups: Restoration tests (not just “having backups”).
Failover strategy: Procedures and monitoring for switching.

3. Storage

Shared storage (NFS/objects): For moodledata according to architecture.
IO Separation: Prevent file uploads from degrading DB performance.

Expected Results

Greater service continuity in case of incidents.
Better support for user peaks (enrolment, exams).
Lower operational risk in updates.