Linux Daily Management

1. Monitor system Status

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The first line from left to right: time, System uptime, number of logged on users, average load (the number of CPU active processes per unit of time (the larger the value, the greater the server pressure, as long as the number of CPUs can be))

(System average load value within 1 minutes, average system load value within5 minutes, average system load value within 15 minutes)

Second line: Currently logged in user, landing point,

2. View CPU Cat/proc/cpuinfo

3. Monitoring System Status Vmstat (specific position of the pressure ) procs, memory, swap, IO, System, CPU.

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R b si so bi bo (focus on)

Proces: Process-related information

R: Indicates the number of processes running and waiting for CPU time slices, if the long-term is greater than the number of server CPUs, it indicates that the CPU is not enough;

B: Indicates the number of processes waiting for the resource, such as waiting for I/O, memory, etc., if the value of this column is longer than 1, then you need to pay attention to it;

Memories: Memory-related information

Swap: Indicates the amount of memory switched to the swap partition

Free: The amount of memory currently idle;

Buff: Buffer size, (will be written to disk);

Cahe: Cache size, (read from disk);

Swap: Memory Exchange situation

Si: The amount of data written to memory by the swap area;

So: The amount of data written to the swap area by memory;

IO: Disk usage

BI: The amount of data read from a block device (read disk);

Bo: The amount of data written from a block device (write disk);

System: Shows the number of interrupts occurring during the acquisition interval

In: Indicates the number of interrupts per device observed at a certain time interval;

CS: Indicates the number of context switches produced per second;

CPU Displays CPU usage status

ID: The percentage of time that the CPU is idle;

WA: Indicates the percentage of CPU time consumed by I/O waits;

ST: Indicates the percentage of the stolen CPU (typically 0, without concern);

High bi bo value when disk IO pressure is large

Si,so high value, and constantly changing, indicating insufficient memory

4.TOP Displays the system resources occupied by the process (dynamic monitoring process takes up system resources, changing every 3 seconds)

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Res: Process consuming memory size

%MEM: Use the memory ratio hungry

Shift+m Sort by memory use size

1 List CPU Usage

TOP-BN1 non-dynamic printing system resource usage all at once all the information is output rather than dynamic display.

5 SAR Monitoring System All resource states (average load, network card traffic, disk status, memory usage) can print historical information displays the system status information from 0 o'clock to the current time on the same day yum Install C7>-y Sysstat

1) Sar-n DEV View network card traffic

2) sar-n DEV 1 5 real-time View network card traffic

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IFACE Device Name

RXPCK/S number of packets per second entered

TXPCK/S the number of packets sent out per second

rxbyt/s amount of data received per second (Byte)

txbyt/s amount of data sent per second

The managed server drops are very serious, see the network card traffic is abnormal, the cleavage rxpck/s>4000 or rxbyt/s>5000000 may be attacked (in addition to copying data)

3) san-n Dev-f/var/log/sa/sa0

-F option to view the network card traffic history of a given day followed by file name

4) sar-q View historical load

6 Free View Memory usage

7 PS Viewing system processes

PS aux display system process

PID process ID Termination process KILL-9 process PID

PS aux | Grep-c Mingetty View a process or its number. The resulting quantity needs to be reduced by 1 (grep itself is also a)

8 Netstat View network status

NETSTAT-LNP printing which ports the current system launches

netstat -an Print network connection status

9 Tcpdump Grab Bag tool

Tcp-nn-i Eth0-nn Let the third and fourth columns appear as ip+ port numbers without-nn the host name + service name is displayed

This article is from the "Exclusive View" blog, please be sure to keep this source http://molujiang.blog.51cto.com/9742572/1878807

Linux Daily Management