Linux Server / Performance, Capacity & Containers
Distinguish Linux swap occupancy from active paging pressure
A server can retain swapped pages after an earlier peak without currently thrashing. Measure current page movement and latency.
Environment and inputs: Linux server baseline · Ubuntu 24.04 LTS / RHEL 9-style systems. Use the specified distribution, init system and installed tool; service names, privileges and supported options can differ.
Start with this check
Confirm the host, shell and access role. Replace sample names, paths, domains and interfaces with approved targets. These are diagnostic commands; assess policy and workload impact before making changes.
vmstat 1 5Read the result
After the initial report, si and so describe sampled swap activity in the tool's documented units. Interpret them with available memory, blocked tasks and application response time.
Resolve and verify
Compare sustained paging with workload concurrency and process memory. Fix excessive demand or capacity rather than treating every nonzero swap total as an incident.
Before changing production
Do not run swapoff on a busy server as a cleanup task; forcing pages back into RAM can create severe pressure.