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LFCS · Question #154
LFCS Question #154: Real Exam Question with Answer & Explanation
The correct answer is A: Resident set size (RSS). Resident Set Size (RSS) is the most critical memory measurement for capacity planning because it reflects the actual physical RAM utilized by a process.
Submitted by helene.fr· Apr 18, 2026Operation of Running Systems
Question
When investigating memory usage, what is the most important measurement for capacity planning purposes?
Options
- AResident set size (RSS)
- BTotal memory
- CVirtual memory size (VSZ)
- DSwap memory usage
Explanation
Resident Set Size (RSS) is the most critical memory measurement for capacity planning because it reflects the actual physical RAM utilized by a process.
Common mistakes.
- B. Total memory refers to the entire RAM installed on the system, which is a static value and not a per-process measurement of usage for capacity planning.
- C. Virtual Memory Size (VSZ) includes all memory a process can access, including mapped files and swapped memory, often overestimating actual physical memory consumption.
- D. Swap memory usage indicates memory moved from RAM to disk, which is a symptom of insufficient physical memory rather than the primary measure of a process's actual RAM footprint.
Concept tested. Memory metrics for capacity planning
Reference. https://perf.wiki.kernel.org/index.php/RSS
Topics
#Memory usage#Capacity planning#Resident Set Size (RSS)
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