Load balancing, caching, CDNs, sharding, replication, queues, consistent hashing and latency numbers.
40 cards · basic cards · AI-written, checked twice. Edit anything.
- What is the primary goal of load balancing?
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Distribute incoming traffic evenly across multiple servers to prevent bottlenecks.- Name three common load balancing algorithms.
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Round robin, least connections, and weighted round robin.- What is a health check in load balancing?
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A periodic test verifying a server is responsive; unhealthy servers are removed from the pool.- What does sticky sessions mean in load balancing?
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Routing all requests from the same client to the same backend server, using cookies or IP hashing.- What is the difference between layer 4 and layer 7 load balancing?
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Layer 4 routes on IP protocol data; layer 7 inspects HTTP headers and can route by URL path or host.- What is the cache hit rate?
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The percentage of data requests satisfied by the cache rather than fetching from slower primary storage.- Name three common cache eviction policies.
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LRU (Least Recently Used), LFU (Least Frequently Used), and FIFO (First In, First Out).- What is cache invalidation?
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Removing or updating stale data in a cache so clients do not receive outdated information.- What is a write-through cache?
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Data is written to both cache and underlying storage simultaneously; guarantees consistency but slower writes.- What is a write-back cache?
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Data is written to cache first and flushed to storage later; faster writes but risk of data loss.- What is cache stampede?
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When a popular cache item expires, many concurrent requests hit the slow backend simultaneously.- What does a CDN do?
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Caches and serves content from servers geographically close to users, reducing latency and bandwidth costs.- Name two ways a CDN reduces latency.
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Geographic distribution of edge servers and local caching of popular content.- What is an edge server?
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A server located closer to end users that caches and serves copies of content, part of the CDN infrastructure.- What types of content are best suited for CDN delivery?
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Static content like images, CSS, JavaScript, and video; anything that changes infrequently.
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