Horizontal scaling, or scaling out, increases capacity by adding more servers or instances that share the load, usually behind a load balancer.
Why it matters
It can grow almost without a ceiling and improves resilience, since losing one node removes only a fraction of capacity. It is the standard approach for web tiers.
It requires applications that work across multiple nodes: sessions and files must not live only on one machine, and databases are harder to scale out than stateless web servers.
Example
A site runs on 2 identical web servers behind a load balancer. Before a sale, the team adds 4 more. Traffic is spread across 6 servers, and each now handles about one third of the original per-server load.
Common mistakes
- Scaling out the web tier while the single database stays the bottleneck.
- Keeping user sessions in local memory so users get logged out when routed elsewhere.
- Differences between nodes (config drift), which cause confusing, inconsistent behavior.
Related
Get notified when this term updates
Plus occasional practical tips on uptime and monitoring, nothing else. Unsubscribe anytime.
यह पेज सामान्य जानकारी है, जिसे हमारी संपादकीय टीम ने लिखा है और दस्तावेज़ीकरण बदलने पर अपडेट किया जाता है। सर्वर और प्रदाता अलग-अलग होते हैं, इसलिए बदलाव पहले सुरक्षित तरीके से जाँचें। देखें: संपादकीय नीति और अस्वीकरण.