Describe How and Why NGINX Uses Shared Memory Zones F5N1 Practice Questions (Page 2)

Questions 6–10

1. 6application · medium

   An NGINX administrator is explaining to a colleague why shared memory zones are necessary for rate limiting. The colleague suggests that each worker process could simply keep its own counters and the rate limit would be 'good enough'. What is the most accurate reason why this approach is insufficient?

   • AEach worker would have a separate counter, so a client could exceed the limit by sending requests to different workers.
   • BShared memory zones are required by the NGINX license for rate limiting.
   • CWorker processes cannot access each other's memory, so counters would be lost when a worker restarts.
   • DThe rate limit would be applied per worker, which is more accurate than a global limit.
   Reveal Solution Discussion Select an answer first
2. 7expert · hard

   An administrator is running NGINX with 16 worker processes on a server with 64 GB of RAM. They are configuring a shared memory zone for rate limiting and need to decide on the zone size. The zone will store keys for up to 200,000 unique IP addresses. What is the minimum zone size that should be allocated to avoid evictions, assuming each key consumes approximately 64 bytes?

   • A16 MB
   • B32 MB
   • C8 MB
   • D64 MB
   Reveal Solution Discussion Select an answer first
4. 8application · medium

   A company is using NGINX as a load balancer for a cluster of backend servers. They want to ensure that requests from the same client are always sent to the same backend server, but they also want to handle clients that may come from different IP addresses (e.g., mobile users switching networks). Which approach should they use?

   • AUse the least_conn directive in the upstream block.
   • BUse the ip_hash directive in the upstream block.
   • CUse the sticky directive with a shared memory zone to persist session-to-backend mappings based on a cookie.
   • DUse the proxy_set_header directive to forward the client IP to the backend.
   Reveal Solution Discussion Select an answer first
5. 9expert · hard

   An NGINX administrator is planning to use a shared memory zone for a feature that tracks user sessions. The sessions are stored in the zone and are updated frequently. The administrator is concerned about the performance impact of frequent updates. What is the most accurate statement about this concern?

   • AFrequent updates to a shared memory zone can cause contention between worker processes, potentially reducing throughput.
   • BFrequent updates require the zone to be stored on disk to avoid memory pressure.
   • CFrequent updates have no performance impact because shared memory is always fast.
   • DFrequent updates are only a concern if the zone is larger than 1 GB.
   Reveal Solution Discussion Select an answer first
6. 10application · medium

   An e-commerce platform uses NGINX as a reverse proxy with multiple worker processes. They want to implement session persistence so that a user's requests are consistently routed to the same backend server. The administrator is considering using the sticky cookie module. What must be configured to ensure session persistence works correctly across all worker processes?

   • ASet the worker_processes directive to auto and increase the keepalive timeout to 300 seconds.
   • BUse the ip_hash directive in the upstream block without any additional configuration.
   • CEnable the proxy_pass directive with a round-robin upstream block and rely on cookies set by the backend.
   • DDefine a shared memory zone in the http block using the sticky directive with the zone parameter.
   Reveal Solution Discussion Select an answer first