Ten (2) nload command, monitor IO performance, free command, PS command, netstat view network status

nload Command (view network card traffic, with Sar-n DEV)

(The system does not install this toolkit by default, yum install-y nload, install nload before installing epel-release)

Use Nload to view network card information, you can see access to the network card information, press the Q key to exit.

Monitoring IO Performance (disk)

Installation: Sysstat package will be installed with Iostat (Iostat and SAR belong to a package)

Iostat-x

%util high value (insufficient disk IO), rkb/s and wkb/s are also very high

%util: As a disk performance judgment

Iotop (see which process is frequently read and write on disk)

First install Yum install-y iotop

Free command (view memory usage)

Free

Free-h (automatically displayed in the appropriate units)

Buff: Buffer cache: Caching

Formula: Total=used+free+buff/cache

avaliable contains free and buffer/cache remaining parts

PS command

(View system process, equivalent to Task Manager under window)

PS aux (View all processes of the system)

Ps-elf and PS aux almost

PID of the process

The Kill + process PID can kill a process

Ls-l/proc/ Process PID can be viewed to the start of the process (directory)--"for the benefit of other virus intrusion view illegal process."

Stat Description:

D a process that cannot be interrupted

The process of R run state

S Process in sleep state

T pause, Stop the process

Z Zombie Process

+ Foreground Process

< high-priority processes (processes are high-priority words will take precedence when CPU is used)

N Low-priority processes

Memory paging is locked in memory

S master Process

L Multithreading Process

View network Status

Netstat (view TCP/IP communication status)

Listening port: For other machines to exchange data with our server, access to the service, you need to provide a listening port.

Viewing port: NETSTAT-LNP (L:listen)

NETSTAT-LTUNP (View only TCP and UDP states)

Netstat-an (view full connection status)

!!! Command: netstat-an | awk '/^tcp/{++sta[$NF]} END {for (key in STA) print key, "\ T", Sta[key]} '

Established: Number of concurrent connections indicates how many clients and service sides are communicating at the same time

Ten (2) nload command, monitor IO performance, free command, PS command, netstat view network status