Top,sar,free and PS commands

Top Dynamic View Load

The default change every 3 seconds, you can also command top-d 1 to make it change every 1 seconds,

Top-c can make it the last column of command source display more detailed, TOP-BN1 can display all processes at once

Top defaults are sorted by CPU usage, and clicking M can also be sorted by memory usage size

Top Results Analysis:

PR: Value range [0,39], process priority;

NI: [ -20,+19] nice value, generally, pr=ni+20;

VIRT: How much virtual memory is used

RES: How much real memory is used

SHR: Shared Memory
S: Indicates a process is in sleep state

%CPU:CPU Utilization

%MEM: Internal Storage Utilization

Time+: Time to use CPU

Command: Source of commands

SAR Multifunction View command

sar-q can view the system load Sar-q-f/var/log/sa/sa20 can view the system payload of number 20th

Sar-b can be disk IO status, Unit K sar-b-f/var/log/sa/sa20 can view disk status of number 20th

Sar-n DEV can view network card traffic Sar-n dev-f/var/log/sa/sa20 can view network card traffic for number 20th

Sar-p can view CPU usage

SAR query results in rxkb/s (in), txkb/s (out), can be seen as the Machine rxkb/s (in) is the download traffic, txkb/s (out) is the upload traffic.

For example: We use this machine as a Web service, we download things from this server remotely with a browser, see txkb/s this one. We download from the server, is the server upload, we upload to the server is the server download.

Free View Memory usage information

Usage: free,free-k, free-m,free-g,free-h

Free Display information:

Buffers and cached represent buffering and caching, buffers is the memory used by the CPU to write the portion of the data or information that is ready to be written to the disk, and cached is the memory used to read from disk to prepare the CPU for processing data or information. The numbers for the buffers and cached columns indicate how much buffers and cached are left, and the first row of the free column represents the amount of memory that can be allocated, plus the remaining memory of buffers and cached is the second row of data that is actually available.

PS Viewing process information

Usage: PS aux, ps-elf

PS Display information:

PID: Process ID, which can be restarted, paused, or killed by this ID;

%cpu/%mem:cup and memory occupancy rate;

Vsz/rss: Virtual memory and physical memory

TTY: Where does the process start? Indicates background

Stat:s sleep S main process or parent process < high priority n Low priority + foreground run R running

L Memory Locked process L multithreaded process Z Zombie process x dead process T paused process D cannot interrupt process

Start: The time the process started;

Time: Using the CPU

Command: Commands or services

This article is from the Linux OPS blog, so be sure to keep this source http://zhumy.blog.51cto.com/11647651/1787554

Top,sar,free and PS commands