vmstat

name	vmstat
description	Report virtual memory and system statistics

vmstat Plugin

Report virtual memory, processes, CPU, I/O, and system statistics.

Quickstart

# One-shot system statistics
vmstat

# Continuous monitoring (every 2 seconds, 5 times)
vmstat 2 5

# Show active/inactive memory
vmstat -a

# Disk statistics
vmstat -d

# Disk summary
vmstat -D

# Partition read/write stats
vmstat -p sda1

# Slab allocator statistics
vmstat -s

# Show version
vmstat --version

Common Flags

Flag	Description
-a	Show active/inactive memory
-d	Disk statistics (read/write per disk)
-D	Disk summary statistics
-p	Partition-specific statistics
-s	Slab allocator statistics
-t	Timestamp on each line
-S	Unit (k/K/m/M)
-w	Wide output

Fields Explained

Field	Description
r	Processes waiting for CPU
b	Processes in uninterruptible sleep
swpd	Used swap memory
free	Free memory
buff	Buffer cache
cache	Page cache
si/so	Swap in/out
bi/bo	Block in/out
us/sy/id/wa	CPU time percentages

Tips

• First line of output shows averages since boot; subsequent lines show delta
• Use delay and count for real-time monitoring
• High wa (wait) indicates I/O bottleneck
• High si/so indicates swapping pressure (needs more RAM)