200.1 Measure and Troubleshoot Resource Usage (weight: 6) LPIC-2 Practice Questions (Page 4)

Questions 16–20

1. 16expert · hard

   A server runs a real-time application that must respond within 10ms. `mpstat -P ALL 1` shows Core 0 at 100% and Core 1 at 5%. `vmstat 1` shows `cs` (context switches) at 50,000 per second. The application is single-threaded and pinned to Core 0. Which action will most likely improve response time?

   • AMove the application to Core 1, which is less utilized
   • BIncrease the application's nice value to give it higher priority
   • CReduce the context switch rate by disabling the kernel's preemption
   • DAdd more CPU cores to the server
   Reveal Solution Discussion Select an answer first
2. 17foundation · easy

   When a system is experiencing high load and you observe that the CPU is mostly idle but the disk I/O wait time is consistently high, which component is most likely the bottleneck?

   • AMemory
   • BNetwork
   • CDisk I/O
   • DCPU
   Reveal Solution Discussion Select an answer first
4. 18expert · hard

   A server runs a Java application and a PostgreSQL database. Users report intermittent slowdowns. `top` shows the Java process at 200% CPU (2 cores) and PostgreSQL at 50% CPU. `free -m` shows 12 GB total, 11.5 GB used, 500 MB available, and 2 GB swap used. `vmstat 1` shows `si`/`so` around 200. The administrator suspects the Java application's heap is too large, forcing the OS to swap. Which action best addresses the root cause without disrupting the database?

   • ASet `vm.overcommit_memory=2` to prevent the kernel from overcommitting memory
   • BAdd more swap space to accommodate the memory demand
   • CIncrease the PostgreSQL shared_buffers to cache more data in memory
   • DReduce the Java heap size via JVM options and restart the Java application
   Reveal Solution Discussion Select an answer first
5. 19foundation · easy

   Which command displays network interface throughput, showing the rate of data transfer (in KB/s) for each interface, and is useful for measuring real-time network usage?

   • Ass
   • Bvmstat
   • Cnetstat
   • Difstat
   Reveal Solution Discussion Select an answer first
6. 20application · medium

   Users report that file transfers to a server are slow, but interactive SSH sessions feel responsive. `ifstat` shows the network interface is transmitting at 90 Mbps on a 100 Mbps link. `iostat -x` shows the disk is 95% utilized. Which component is the bottleneck?

   • AThe network interface, because it is nearly saturated at 90% of its capacity
   • BThe CPU, because it must process network packets and disk I/O simultaneously
   • CThe memory, because buffering file transfers requires significant RAM
   • DThe disk subsystem, because it is 95% utilized and file transfers require disk writes
   Reveal Solution Discussion Select an answer first