What is vmstat command?
The vmstat command (short for virtual memory statistics) is a built-in monitoring utility in Linux. The command is used to obtain information about memory, system processes, paging, interrupts, block I/O, disk, and CPU scheduling. Users can observe system activity virtually in real-time by specifying a sampling period.
What is the use of iostat and vmstat commands?
These comes built in with the operating system and are easy to use . iostat stands for input output statistics and reports statistics for i/o devices such as disk drive. vmstat gives the statistics for virtual Memory and netstat gives the network statistics .
What is vmstat used for?
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.
What is difference between SAR and vmstat in Linux?
I managed to figure out the difference of swap data: for sar uses 512-bytes bloks, while vmstat uses kbytes. that makes the numbers somewhat alike. but when it comes to freememory, things are a little bit more difficult.
What is the use of vmstat in tuning?
Use the vmstat ( vm_stat on Mac OS X) or sar command to monitor paging. The following table lists the important columns from the output of these commands. Indicates the number of address translation page faults. Address translation faults occur when a process refers to a valid page not in memory.
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 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 The vmstat command do in Linux?
vmstat command in Linux/Unix is a performance monitoring command of the system as it gives the information about processes, memory, paging, block IO, disk and CPU scheduling.
Why does The vmstat command return inconsistent statistics?
The vmstat command might return inconsistent statistics because the statistics are not read atomically. If you run the vmstat command without flags, the report contains a summary of the virtual memory activity since system startup.
How does The vmstat command report the number of Forks?
If you specify the -f flag, the vmstat command reports the number of forks since system startup. The physicalvolume parameter specifies the name of the physical volume. The interval parameter specifies the amount of time in seconds between each report.
What does inactive memory mean in vmstat command?
Inactive memory is memory that was allocated to a process which is no longer running. Using the -a option replaces the buff and cache memory columns with inact and active columns. These columns display the amount of inactive and active memory in a system.