vmstat
system monitoringLinux/Unix
The vmstat command is one of the most frequently used commands in Linux/Unix-like operating systems. vmstat Report virtual memory statistics
Quick Reference
Command Name:
vmstat
Category:
system monitoring
Platform:
Linux/Unix
Basic Usage:
vmstat [options] [arguments]
Common Use Cases
Syntax
vmstat [options] [delay [count]]
Options
Option | Description |
---|---|
-a, --active |
Display active and inactive memory |
-f, --forks |
Display number of forks since boot |
-m, --slabs |
Display slabinfo |
-n, --one-header |
Display header only once |
-s, --stats |
Display event counters and memory statistics |
-d, --disk |
Display disk statistics |
-D, --disk-sum |
Display disk summary |
-p, --partition device |
Display partition specific statistics |
-S, --unit character |
Define display unit (k, K, m, M) for size output |
-t, --timestamp |
Display timestamp with each update |
-w, --wide |
Use wide output format |
-V, --version |
Display version information |
-h, --help |
Display help information |
delay |
Delay between updates in seconds |
count |
Number of updates to display |
vmstat Output Fields
Procs
Field | Description |
---|---|
r | Number of processes waiting for run time |
b | Number of processes in uninterruptible sleep |
Memory
Field | Description |
---|---|
swpd | Virtual memory used (swap) |
free | Idle memory |
buff | Memory used as buffers |
cache | Memory used as cache |
inact | Inactive memory (with -a option) |
active | Active memory (with -a option) |
Swap
Field | Description |
---|---|
si | Memory swapped in from disk (KB/s) |
so | Memory swapped out to disk (KB/s) |
I/O
Field | Description |
---|---|
bi | Blocks received from a block device (blocks/s) |
bo | Blocks sent to a block device (blocks/s) |
System
Field | Description |
---|---|
in | Interrupts per second, including the clock |
cs | Context switches per second |
CPU
Field | Description |
---|---|
us | Time spent running non-kernel code (user time, including nice time) |
sy | Time spent running kernel code (system time) |
id | Time spent idle |
wa | Time spent waiting for IO |
st | Time stolen from a virtual machine |
Examples
How to Use These Examples
The examples below show common ways to use the vmstat
command. Try them in your terminal to see the results. You can copy any example by clicking on the code block.
# Basic Examples Basic
# Display a snapshot of virtual memory statistics
vmstat