CompTIA Linux+ (XK0-006)TroubleshootingEasy
A technician runs `free -h` on a server that appears sluggish: total used free shared buff/cache available Mem: 15Gi 2.1Gi 1.2Gi 200Mi 12Gi 13Gi Which column should the technician check to determine how much memory is actually available for new applications?
- Afree
- Bavailable
- Cused
- Dbuff/cache
Show answer & explanationAnswer & explanation
Correct answer: B. available
The 'available' column estimates memory that can be given to new processes without swapping, including memory that can be reclaimed from the buffer/cache. The 'free' column only shows completely unused memory and is misleading on Linux systems.
Why the other options are wrong
- A. free only shows totally unused RAM, ignoring reclaimable cache.
- C. used shows memory actively allocated, not what's available for new processes.
- D. buff/cache is memory used for disk caching, not directly the available metric.
free -h available column
The 'available' column in free output estimates usable memory for new applications, factoring in reclaimable cache/buffers.
- Linux uses free RAM for disk caching (buff/cache)
- 'free' alone underestimates usable memory
- 'available' is the correct metric to judge memory pressure
Memory trick: Available = Actually-usable memory (cache can be dropped)