View system resources, loads, and performance monitoring in linux

 

1. View Disks

Df-h

2. view the memory size.

Free

Free [-m | g] memory display by MB, GB

Vmstat

3. View cpu

Cat/proc/cpuinfo

Only check the number of CPUs grep "model name"/proc/cpuinfo | wc-l

4. view system memory

Cat/proc/meminfo

5. view the status of each process

Cat/proc/5346/status 5347 is pid

6. view the load

W

Uptime

7. view the overall system status

Top

Finally, some output information is explained as follows:

Load average: 0.09, 0.05, 0.01

The three numbers represent the average system load (one minute, five minutes, and fifteen minutes) in different time periods. The smaller the number, the better. "How many cores is the load" rule: in multi-core processing, the average value of your system should not be higher than the total number of processor cores.

The memory used by the process can be top, with three columns virt res shr, indicating the memory used by the process. VIRT indicates the total memory size that can be used by the process, including the memory actually used by the process, the mapped files, and the memory shared with other processes. RES indicates the memory occupied by the process. SHR identifies the memory and library size that can be shared with other processes.

8. Performance monitoring sar command

The sar-u output shows CPU information. -U option is the default option of sar. This output shows CPU usage in percentage

 

CPU

CPU ID

% User

Duration of running a process in user mode

% Nice

Time taken to run a normal process

% System

Duration of running a process in kernel mode (system)

% Iowait

When no process is executed on this CPU, the time the processor waits for I/O to complete

% Idle

No process execution time on this CPU

 

Sar 5 10 sar obtains 10 samples at intervals of 5 seconds

Sar-u-p ALL 5 5 minute cup display

Sar-n {DEV | EDEV | NFS | NFSD | SOCK | ALL}

Sar provides six different syntax options to display network information. The-n option uses six different switches: DEV | EDEV | NFS | NFSD | SOCK | ALL. DEV displays network interface information, EDEV displays statistics on network errors, NFS statistics on active NFS clients, NFSD statistics on NFS servers, and SOCK displays socket information, ALL shows ALL 5 switches. They can be used independently or together.

Meaning of parameters of sar-n DEV

IFACE

LAN interface

Rxpck/s

Packets received per second

Txpck/s

Packets sent per second

Rxbyt/s

Number of bytes received per second

Txbyt/s

Number of bytes sent per second

Rxcmp/s

Compressed data packets received per second

Txcmp/s

Compressed data packets sent per second

Rxmcst/s

Multicast data packets received per second

9. view the command history (including timestamp)

Export HISTTIMEFORMAT = '% F % T'; history | more

 

10. view the folder and file size.

Du-h -- max-depth = 0 dm view dm directory size

Du-h -- max-depth = 1 dm view the dm directory size and the size of each dm file folder

Du-h -- max-depth = 0 view the current folder size

 

Author Alan Liu