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What is free in vmstat?
free displays the total amount of free and used physical and swap memory in the system, as well as the buffers used by the kernel. vmstat reports information about processes, memory, paging, block IO, traps, and cpu activity.
What is the use of vmstat in Linux and troubleshooting?
The vmstat (virtual memory statistics) command allows you to monitor your system’s memory usage. It shows how much virtual memory there is, and how much is free and paging activity. You can observe page-ins and page-outs as they happen.
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 does free command do in Linux?
The free command gives information about used and unused memory usage and swap memory of a system. By default, it displays memory in kb (kilobytes). Memory mainly consists of RAM (random access memory) and swap memory.
How do I use Vmstat?
How to Use vmstat
- If you don’t have vmstat on your machine, install it by running:
- Enter your password and wait for the installation to finish.
- Run vmstat without parameters to display a system report with average statistics since the last boot.
- For additional reports, use vmstat options, delay, and count.
What do I need to know about vmstat?
The number of processes waiting for run time. The number of processes in uninterruptible sleep. The amount of virtual memory used. The amount of idle memory. The amount of memory used as buffers. The amount of memory used as cache. The amount of inactive memory. ( -a option). The amount of active memory. ( -a option).
What does swpd mean in the Linux kernel?
The swpd field indicates how much swap space has been used; this value increases when your systems physical memory is full and the Linux kernel starts to use the swap partition/file.
What does the final field St mean in vmstat?
The final field st represents the percentage of time a virtual CPU waits for a real CPU while the hypervisor is servicing another virtual processor. Essentially, the steal time cycle counts the amount of time that your virtual machine is ready to run but could not run due to other virtual machines competing for the CPU.
What does the-F switch do in vmstat?
In absence of count, when delay is defined, default is infinite. Display active and inactive memory, given a 2.5.41 kernel or newer. The -f switch displays the number of forks since boot, which includes the fork, vfork, and clone system calls, and is equivalent to the total number of tasks created.