Quickly observe system CPU, memory, swap and I/O activity from the command line. 27.05.2026 | reading time: 3 min vmstat reports essential kernel-level statistics about processes, memory, swap, I/O and CPU so you can spot bottlenecks fast; run it to see live counters instead of guessing what the kernel is doing. Real run: snapshot in the shell Try this: run `vmstat 1 5` to sample every second five times and watch changes; a typical session looks like this: ```bash $ vmstat 1 5 procs -----------memory---------- ---swap-- -----io---- -system-- ------cpu----- r b swpd free buff cache si so bi bo in cs us sy id wa st 2 0 0 104856 12960 142300 0 0 1 2 64 120 1 0 99 0 0 0 0 0 104900 12960 142320 0 0 0 0 30 40 0 0 100 0 0 0 0 0 104900 12960 142320 0 0 0 0 28 36 0 0 100 0 0 0 0 0 104900 12960 142320 0 0 0 0 29 38 0 0 100 0 0 ``` Options that change the view Use `vmstat -s` for cumulative counters, `vmstat -a` to split active and inactive memory, and `vmstat -m` to inspect slab caches; for repeated sampling just pass interval and count like `vmstat 2 10` and watch trends rather than single snapshots. When to rely on vmstat Use vmstat to answer concrete questions: is the CPU idle or waiting on I/O, is swap activity high, are runnable processes queuing; it is not a per-process profiler, but it quickly narrows whether the problem is CPU, memory, swap, or I/O related. Tools that pair well with vmstat Combine vmstat with `iostat` to detail disk waits, `pidstat` or `top` to find a noisy process, and `sar` for long-term historical trends; start with vmstat to classify the problem, then dig deeper with the appropriate tool. Finish line and next step vmstat gives a fast, low-overhead view of system health and points your investigation into CPU, memory, swap, or I/O; practice reading its counters on live systems, then level up your skills and consider formal certification through resources like bitsandbytes.academy to prepare for CompTIA Linux+ or LPIC-1. Join Bits & Bytes Academy First class LINUX exam preparation. utilities processes troubleshooting infrastructure
