Linux Commands / IT Support Guides
Read Linux memory pressure with free
A large used-memory number is not enough to diagnose a Linux memory problem. The kernel deliberately uses spare RAM for caches that may be reclaimable.
Environment and inputs: Linux · Bash-compatible shell; package and service names vary by distribution
Try the diagnostic command
Use the stated shell and platform. Replace sample domains, addresses, services and paths with values from the system you are authorized to support.
free -hHow to read the result
Focus on available memory alongside swap usage and the workload. Available estimates memory usable by new applications without swapping; free alone omits useful reclaimable capacity.
What to do next
Observe the values during the slowdown and correlate them with process memory and kernel out-of-memory events. Determine whether pressure is sustained before resizing the machine.
Before you make a change
Swap in use can remain after an earlier pressure event. A single sample does not establish current paging activity or an application's memory leak.