Cheatsheet & Examples: vmstat
vmstat (Virtual Memory Statistics) provides a real-time view of system performance by reporting statistics about processes, memory, paging, I/O, CPU activity, and other aspects of system performance. It's a useful tool for identifying performance bottlenecks.
Displaying System Performance Snapshot
Example Usage:
vmstat 1
What it does: Displays a single snapshot of system statistics with a 1-second interval.
Command-line Arguments Explained:
1: The interval in seconds between each update. In this case, it refreshes the output every second.
Continuously Monitoring System Performance
Example Usage:
vmstat 5 3
What it does: Displays system statistics repeatedly, updating every 5 seconds, and showing 3 updates total.
Command-line Arguments Explained:
5: The interval in seconds between each update.3: The number of updates to display. If omitted, vmstat will run indefinitely.
Displaying Specific Statistics with -a option
Example Usage:
vmstat -a 5 2
What it does: Displays more detailed memory statistics, including active and inactive memory. This can be helpful for understanding memory usage patterns. It refreshes the output every 5 seconds and shows 2 updates total.
Command-line Arguments Explained:
-a: Displays active and inactive memory statistics.5: The interval in seconds between each update.2: The number of updates to display.
Displaying Disk Statistics
Example Usage:
vmstat -d 5 2
What it does: Displays disk statistics, offering insights into disk I/O performance. It refreshes the output every 5 seconds and shows 2 updates total.
Command-line Arguments Explained:
-d: Displays disk statistics.5: The interval in seconds between each update.2: The number of updates to display.
Displaying Disk Statistics and Processes information
Example Usage:
vmstat -d -p 5 2
What it does: Displays both disk statistics and process information, offering a more comprehensive view of system resource usage, focusing on disk I/O, it refreshes the output every 5 seconds and shows 2 updates total.
Command-line Arguments Explained:
-d: Displays disk statistics.-p: Displays process information5: The interval in seconds between each update.2: The number of updates to display.
Displaying Memory Statistics and Processes information
Example Usage:
vmstat -m -p 5 2
What it does: Displays both memory statistics and process information, offering a more comprehensive view of system resource usage, focusing on memory and process state, it refreshes the output every 5 seconds and shows 2 updates total.
Command-line Arguments Explained:
-m: Displays memory statistics.-p: Displays process information5: The interval in seconds between each update.2: The number of updates to display.
Displaying Slabinfo Information
Example Usage:
vmstat -S 5 2
What it does: Displays slabinfo, providing insights into the kernel's memory allocation efficiency. It refreshes the output every 5 seconds and shows 2 updates total.
Command-line Arguments Explained:
-S: Displays slabinfo statistics.5: The interval in seconds between each update.2: The number of updates to display.
