vmstat
Report virtual memory and system statistics
TLDR
Display virtual memory statistics
$ vmstat
Display reports every 2 seconds, 5 times$ vmstat 2 5
Display active/inactive memory$ vmstat -a
Display disk statistics$ vmstat -d
Display slab information$ vmstat -m
Display event counters and memory stats$ vmstat -s
Display with timestamp$ vmstat -t 1
SYNOPSIS
vmstat [options] [delay [count]]
DESCRIPTION
vmstat reports information about processes, memory, paging, block IO, traps, disks, and CPU activity. The first report shows averages since boot; subsequent reports show activity during the sampling period.
PARAMETERS
-a, --active
Display active and inactive memory-f, --forks
Display number of forks since boot-m, --slabs
Display slab information-s, --stats
Display event counters and memory statistics-d, --disk
Report disk statistics-D, --disk-sum
Report summary disk statistics-p, --partition DEVICE
Detailed partition statistics-n, --one-header
Print header only once-t, --timestamp
Append timestamp to each line-w, --wide
Wide output mode-y, --no-first
Omit first report (boot statistics)-S, --unit UNIT
Switch output units (k, K, m, M)
OUTPUT FIELDS
Procs: r (runnable), b (blocked)
Memory: swpd, free, buff, cache
Swap: si (in), so (out)
IO: bi (blocks in), bo (blocks out)
System: in (interrupts), cs (context switches)
CPU: us (user), sy (system), id (idle), wa (wait), st (stolen)
CAVEATS
The first report shows averages since boot. Use -y to omit it. Wide mode (-w) is recommended for systems with large amounts of memory.
HISTORY
vmstat is part of procps-ng, providing virtual memory statistics since early Unix systems.