Describe Why Directives Use a Shared Memory Zone F5N1 Practice Questions (Page 1)

Questions 1–5

1. 1expert · hard

   A company uses NGINX with 8 worker processes. They have configured the sticky directive with a shared memory zone of 512 KB. The server handles 5,000 concurrent users. The administrator notices that some users are being routed to different upstream servers between requests, breaking session affinity. What is the most likely cause and solution?

   • AThe shared memory zone is too small, causing session mappings to be evicted; increase the zone size
   • BThe sticky directive is not compatible with multiple worker processes; use a single worker
   • CThe worker processes are not using the same configuration file; ensure all workers use the same config
   • DThe master process is reassigning sessions to balance load; disable load balancing
   Reveal Solution Discussion Select an answer first
2. 2foundation · easy

   What is the main advantage of using shared memory for inter-process communication in NGINX compared to other methods?

   • AIt allows each worker to have a private copy of the data for better performance.
   • BIt automatically persists data across NGINX restarts.
   • CIt allows communication between NGINX and external applications without network configuration.
   • DIt provides a fast, low-overhead way for worker processes to share data without copying or serialization.
   Reveal Solution Discussion Select an answer first
4. 3foundation · easy

   How does a shared memory zone ensure data consistency across NGINX worker processes?

   • ABy providing a single memory region that all worker processes read from and write to, with locking mechanisms to prevent conflicts.
   • BBy using a master process to periodically copy data from each worker to the others.
   • CBy allowing each worker process to have its own copy of the data and synchronizing via disk writes.
   • DBy using a separate process to manage all state and communicate with workers via sockets.
   Reveal Solution Discussion Select an answer first
5. 4application · medium

   An NGINX server is configured with 4 worker processes. The administrator wants to use the limit_conn_zone directive to limit the number of concurrent connections per IP address. They notice that without a shared memory zone, the limit does not work as expected. What is the most likely reason for this behavior?

   • AThe worker processes are not aware of each other's existence
   • BThe master process cannot read the connection counters from the worker processes
   • CThe connection counters are stored in a file that is not updated in real time
   • DEach worker process maintains its own connection counter, so a client can exceed the limit by connecting to different workers
   Reveal Solution Discussion Select an answer first
6. 5expert · hard

   An NGINX administrator is planning to deploy a new service that requires both rate limiting and sticky sessions. They want to minimize memory usage while ensuring both features work correctly. What is the best approach?

   • AUse a file-based storage for rate limiting and a shared memory zone for sticky sessions
   • BUse separate shared memory zones for rate limiting and sticky sessions
   • CUse a shared memory zone for rate limiting and a database for sticky sessions
   • DUse a single shared memory zone for both rate limiting and sticky sessions
   Reveal Solution Discussion Select an answer first