How do you read vmstat

If there is a non-zero number in that column constantly, you can investigate further with iostat. Analyzing memory related issues should start with checking the amount of free memory in the vmstat output, which is in the 4th column.

If free memory is low, we need to investigate more on which process is consuming more memory. The vmstat command can be a useful tool for triaging performance problems.

It can tell you which subsystems to examine more closely to further diagnose the problem. Skip to primary navigation Skip to main content Skip to primary sidebar Skip to footer navigation. Using iostat to monitor system performance in Linux Examples included.

You May Also Like. Number of processes that are in a wait state. To get a timestamp along with a requested output, use the -t option:. The output is the same as the basic vmstat output, with an added timestamp. The [delay] syntax specifies the time elapsed between each output update, expressed in seconds.

Use the following syntax:. If no delay is specified, only one output is printed, giving average values since the last reboot. To avoid the extra load, use a count value along with a delay value. The syntax is vmstat [delay[count]] , and it is explained in detail in the following section.

The count value lets vmstat know how many updates to carry out before the output stops refreshing. To run a command an infinite number of times, omit the [count] syntax. The syntax for using the count value is:. The default unit for displaying memory and swap statistics is kilobytes. To change the output units, use the -S option and one of the following arguments:.

To display the statistics in decimal kilobytes and megabytes, use k and m , respectively. Upper case K and M display statistics in hexadecimal kilobytes and megabytes.

For example, use the following command to update the statistics every 5 seconds and to change the display units to megabytes:. Slab allocation is a memory management system for efficiently allocating memory to various data objects that the kernel handles. Topics: Linux. Tyler Carrigan Tyler is a community manager at Enable Sysadmin, a submarine veteran, and an all-round tech enthusiast!

On Demand: Red Hat Summit Virtual Experience Relive our April event with demos, keynotes, and technical sessions from experts, all available on demand. Watch Now. Related Content Image. Build a lab in 36 seconds, run Podman on a Mac, and more tips for sysadmins. Check out Enable Sysadmin's top 10 articles from October Posted: November 2, Author: Vicki Walker Red Hat.

How to package open source applications as RPMs. Want to use a piece of third-party software but there's no RPM to install it? How to Check Queue Activity sar -q. How to Check Unused Memory sar -r.

How to Check System Table Status sar -v. How to Check Swapping Activity sar -w. How to Check Terminal Activity sar -y. Collecting System Activity Data Automatically sar. Running the sadc Command When Booting. Running the sadc Command Periodically With the sa1 Script.

Producing Reports With the sa2 Shell Script. Setting Up Automatic Data Collection sar. Managing Software Packages Tasks. Managing Disk Use Tasks. Scheduling System Tasks Tasks. Managing System Crash Information Tasks. Managing Core Files Tasks. Troubleshooting System and Software Problems Tasks. You can use the vmstat command to report virtual memory statistics and information about system events such as CPU load, paging, number of context switches, device interrupts, and system calls.

The vmstat command can also display statistics on swapping, cache flushing, and interrupts. For a more detailed description of this command, see the vmstat 1M man page. The following example shows the vmstat display of statistics that were gathered at five-second intervals:.