Linux vmstat Command Tutorial for Beginners

1. How do I start Vmstat?
2. What is the vmstat command in Linux?
3. How do I use Vmstat?
4. What should I look for in Vmstat?
5. What does Iostat command do in Linux?
6. What is available in free command in Linux?
7. What is sar command?
8. How do I check Iostat?
9. How do I see CPU usage on Linux?
10. What is R and B in Vmstat?
11. What is block device in Linux?
12. What is swap memory in Linux?

How do I start Vmstat?

Time stamp: Vmstat command with -t option shows timestamp with every updation. Example: Along with the process there lies time of each update. By default memory status is shown in kilobytes, but when we want to see it in other forms we need a different command.

What is the vmstat command in Linux?

Virtual memory statistics reporter, also known as vmstat , is a Linux command-line tool that reports various bits of system information. Things like memory, paging, processes, IO, CPU, and disk scheduling are all included in the array of information provided.

How do I use Vmstat?

How to Use vmstat

1. If you don't have vmstat on your machine, install it by running: ...
2. Enter your password and wait for the installation to finish.
3. Run vmstat without parameters to display a system report with average statistics since the last boot.
4. For additional reports, use vmstat options, delay, and count.

What should I look for in Vmstat?

What to Look for in vmstat

• r (runqueue) The runqueue value shows the number of tasks executing and waiting for CPU resources. ...
• pi (page in) A page-in operation occurs when the server is experiencing a shortage of RAM memory. ...
• us (user CPU) This is the amount of CPU that is servicing user tasks.

What does Iostat command do in Linux?

The iostat command is used for monitoring system input/output device loading by observing the time the devices are active in relation to their average transfer rates. The iostat command generates reports that can be used to change system configuration to better balance the input/output load between physical disks.

What is available in free command in Linux?

In Linux systems, you can use the free command to get a detailed report on the system's memory usage. The free command provides information about the total amount of the physical and swap memory, as well as the free and used memory.

What is sar command?

SAR stands for System Activity Report, as its name suggest sar command is used to collect,report & save CPU, Memory, I/O usage in Unix like operating system. SAR command produce the reports on the fly and can also save the reports in the log files as well.

How do I check Iostat?

The command to display only a specific device is iostat -p DEVICE (Where DEVICE is the name of the drive--such as sda or sdb). You can combine that option with the -m option, as in iostat -m -p sdb, to display the statistics of a single drive in a more readable format (Figure C). Easy to read stats for a single device.

How do I see CPU usage on Linux?

14 Command Line Tools to Check CPU Usage in Linux

1. 1) Top. The top command displays real-time view of performance-related data of all running processes in a system. ...
2. 2) Iostat. ...
3. 3) Vmstat. ...
4. 4) Mpstat. ...
5. 5) Sar. ...
6. 6) CoreFreq. ...
7. 7) Htop. ...
8. 8) Nmon.

What is R and B in Vmstat?

(Source man vmstat): Procs r: The number of processes waiting for run time. b: The number of processes in uninterruptible sleep. Memory swpd: the amount of virtual memory used. free: the amount of idle memory.

What is block device in Linux?

Block devices are characterized by random access to data organized in fixed-size blocks. Examples of such devices are hard drives, CD-ROM drives, RAM disks, etc. ... To simplify work with block devices, the Linux kernel provides an entire subsystem called the block I/O (or block layer) subsystem.

What is swap memory in Linux?

Swap is a space on a disk that is used when the amount of physical RAM memory is full. When a Linux system runs out of RAM, inactive pages are moved from the RAM to the swap space. Swap space can take the form of either a dedicated swap partition or a swap file.