What is the vmstat command used for?
The vmstat command reports statistics about kernel threads, virtual memory, disks, hypervisor pages, traps, and processor activity. Reports that are generated by the vmstat command can be used to balance system load activity.
What is AVM in vmstat command?
AVM is Active virtual memory and it includes allocated virtual pages. including paging space. fre is the number of real memory pages on the free list.
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.
How do you understand top command?
S – indicates the status of the process: S=sleep R=running Z=zombie (S) %CPU – This is the percentage of CPU used by this process (0.3) %MEM – This is the percentage of RAM used by the process (0.7) TIME+ –This is the total time of activity of this process (0:17.75)
How do I see zombie processes?
Zombie processes can be found easily with the ps command. Within the ps output there is a STAT column which will show the processes current status, a zombie process will have Z as the status. In addition to the STAT column zombies commonly have the words in the CMD column as well.
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 can I use The vmstat command for?
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.
How to show vmstat time stamp in Linux?
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. With paramenter -S M : Displays memory status in Megabytes.
How to show memory status in megabytes in vmstat?
With paramenter -S M : Displays memory status in Megabytes. Example: The memory is shown in MB here in the given figure. -n One header: It is used to display header only once rather than periodically.
What does the F switch on vmstat show?
The -f switch displays the number of forks since boot. This includes the fork, vfork, and clone system calls, and is equivalent to the total number of tasks created. Each process is represented by one or more tasks, depending on thread usage. This display does not repeat. The -m displays slabinfo.