Linux Performance Detection Tool Vmstat command

The Linux Performance Detection Tool VMSTAT command provides monitoring of information such as processes, memory, page I/O blocks, and CPUs, Vmstat can display the average or sampled values of the test results, and the sampling mode can provide a monitoring result of different frequencies over a sampling period.

Linux Performance Detection Tool vmstat command process (procs)
R: Number of processes waiting for run time
B: Process in non-disruptive sleep state
W: Processes that are swapped out but can still be run, this value is calculated

· Linux Performance Detection Tool vmstat command MEMORYSWPD: Number of virtual memory
Free: The number of idle memory
Buff: The amount of memory used as a buffer

Linux Performance Detection Tool vmstat command swap
Si: Quantity exchanged from hard disk
So: The number of swapped to the hard drive

Linux Performance Detection Tool Vmstat command · Io
BI: Number of blocks output to a single block device
Bo: Number of blocks accepted from a single block device

Linux Performance Detection Tool VMSTAT command system
In: Number of interrupts per second, including clock
CS: Number of context switches that occur per second

· Linux Performance Detection Tool vmstat command CPU (% of total CPU uptime)
US: Time for non-kernel code to run (user time, including nice time)
SY: Kernel code run time (System time)
ID: Idle time, in the kernel version prior to Linux 2.5.41, this value includes I/O wait time;
WA: Time to wait for I/O operation, this value is 0 in the kernel version prior to Linux 2.5.41

The Vmstat command provides a number of additional parameters, and some of the most useful parameters are listed below:
Reference
• M: Showing memory utilization of the kernel
A: Display memory page information, including active and inactive memory pages
• N: Displays the header line, which is useful when using sampling mode and outputting command results to a file. For example, Root#vmstat–n 2 10 displays 10 output results at 2-second frequency
• Vmstat provides statistics on I/O results when using the-p {partition}

Vmstat is an abbreviation for virtual meomory Statistics (dummy memory statistics) that monitors the operating system's virtual memory, processes, and CPU activity. He is a statistical analysis of the overall situation of the system, and the disadvantage is that a process cannot be analyzed in depth. Usually use Vmstat 5 5 (which means to generate data every 5 seconds and generate 5 data) command tests. Will get a summary of the data he can reflect the real system situation.
#vmstat 5 5
procs-----------Memory-------------Swap-------io------System------CPU----
R b swpd free buff cache si so bi bo in CS US sy ID WA
1 0 62792 3460 9116 88092 6 30 189 89 1061 569 17 28 54 2
0 0 62792 3400 9124 88092 0 00 14 884 434 4 14 81 0
0 0 62792 3400 9132 88092 0 00 14 877 424 4 15 81 0
1 0 62792 3400 9140 88092 0 00 14 868 418 6 20 74 0
1 0 62792 3400 9148 88092 0 00 15 847 400 9 25 67 0
The Linux memory Monitor vmstat command output is divided into six sections:

(1) process procs:
R: The number of processes waiting in the run queue.
B: The number of processes waiting for IO.

(2) Linux Memory monitoring memory Memoy:
SWPD: Current swap memory available (in kilobytes).
Free: Idle memory (in kilobytes).
Buff: The amount of memory to buffer (in kilobytes).
Cache: The amount of memory that is used as a cache (in kilobytes).

(3) Linux Memory monitor swap swap page
Si: The number of swap pages, in kb/seconds, from disk swap to memory.
So: the number of swap pages from memory swap to disk, in kb/seconds.

(4) Linux Memory Monitoring IO block devices:
BI: The number of blocks sent to the block device, in blocks per second.
Bo: The number of blocks received from the block device, in blocks per second.

(5) Linux Memory Monitoring System :
In: Number of interrupts per second, including clock interrupts.
CS: The number of environment (context) conversions per second.

(6) Linux memory monitoring CPU central Processor:
CS: The time that the user process used. expressed as a percentage.
SY: The time that the system process was used. expressed as a percentage.
ID: The idle time of the central processing Unit. expressed as a percentage.

If R is often greater than 4, and the ID is often less than 40, it means that the CPU is heavily loaded. If the Bi,bo is not equal to 0 long, the physical memory capacity is too small.

Linux Performance Detection Tool Vmstat command