What is the difference between Layer 4 and Layer 7 load balancing?
Layer 4 load balancing operates on the transport layer: it forwards TCP/UDP connections based on IP addresses and ports without looking inside the packets — very fast and protocol-agnostic, but unaware of application content. Layer 7 load balancing understands the application protocol (typically HTTP): it can route based on the URL path, host header, cookies, or method (e.g. send /api to one pool and /images to another), terminate TLS, and do content-based routing. L7 is more flexible and feature-rich; L4 is lower-latency and simpler.
2 / 5
How does round-robin differ from least-connections load balancing?
Round-robin distributes requests by simply cycling through the server list in order — simple and fair when requests are uniform. But if some requests are long-running, a server can accumulate heavy work while others sit idle. Least-connections adapts by routing each new request to the server with the fewest active connections, which better balances load when request durations vary widely. Weighted variants of both let you account for servers of different capacities. The right choice depends on how uniform your request workloads are.
3 / 5
What is a health check in load balancing, and what does it enable?
A health check is a probe (a TCP connect, or an HTTP request to a /health endpoint) the load balancer issues to each backend at intervals. If a server fails the check (timeouts, error status, too few successes), the load balancer removes it from the rotation so no traffic is sent to a broken instance; when it passes again, it is restored. This is what makes a pool self-healing and enables zero-downtime deploys (a draining server fails readiness and is gracefully removed). Good health checks reflect real readiness, not just "the process is up."
4 / 5
What is session affinity (sticky sessions) and what is its drawback?
Session affinity (sticky sessions) ensures a client's requests always reach the same backend, typically tracked via a cookie or source IP. It is useful when a server holds local session state, so the client must return to the server that has its data. The drawbacks: load becomes uneven (some servers get busier clients), scaling is harder (new servers do not help existing sticky clients), and a server failure loses those sessions. The better long-term fix is to externalize session state (e.g. Redis) so any server can handle any request, removing the need for stickiness.
5 / 5
What problem does consistent hashing solve in distributing requests across servers?
With naive hash(key) % N distribution, changing N (adding/removing a server) changes the modulus and reshuffles nearly every key to a different server — catastrophic for caches (mass invalidation) or stateful sharding. Consistent hashing places servers and keys on a hash ring; a key maps to the next server clockwise. When a server is added or removed, only the keys in its arc move — roughly 1/N of keys — leaving the rest stable. Virtual nodes smooth out distribution. It is fundamental to distributed caches (e.g. Memcached clients) and sharded data stores.
What does the "Load Balancing Strategies" vocabulary exercise cover?
This exercise tests real IT vocabulary related to load balancing strategies through 5 multiple-choice questions, each built from realistic workplace sentences rather than abstract definitions.
Is this vocabulary exercise free to use?
Yes. Every exercise on CoderSlingo, including this one, is completely free — no account, sign-up, or payment required.
How many questions does this exercise have?
This exercise has 5 questions. Each one shows a real-world sentence or scenario with multiple-choice options and an explanation once you answer.
What happens after I answer a question?
You'll see immediate feedback showing whether your answer was correct, along with a short explanation of why — then a button to move to the next question, and a full results screen at the end.
Can I retry the exercise if I get questions wrong?
Yes. Once you reach the results screen, click "Try again" to reset your answers and go through the exercise from the start as many times as you like.
Do I need to create an account to take this exercise?
No account is needed. Your answers are scored in your browser during the session — nothing is saved to a server, so you can jump straight in.
Is my progress saved if I leave the page?
No — progress within an exercise resets if you navigate away or reload. Each exercise is short enough to complete in a few minutes in one sitting.
Are these vocabulary exercises connected to other topics?
Yes — this module shares real-world context with 14 other vocabulary modules. See "Related vocabulary" below to keep building a connected skill set.
How is this different from reading a glossary or blog article?
Exercises like this one are active recall drills — you have to choose the correct term or phrasing yourself, which builds retention faster than passively reading a definition.
Where can I find more vocabulary exercises?
Browse the full Vocabulary exercises hub for hundreds of modules covering Agile, DevOps, security, databases, architecture, and more — organised by IT role and skill.