19, the Linux command to monitor the server memory

monitoring Linux Server memory

International practice, we need to know what is the server's memory, what is the function of memory. This is not too much to introduce, Linux performance monitoring requires us to have a certain understanding of the bottom. Below I will list the tools I use to monitor memory.

Vmstat

Vmstat displays information about processes, memory, pages, blocks i/o,traps, and CPUs. Vmstat can display both averages and real-time data. The sampling mode of the Vmstat can be turned on by providing sampling frequency and sampling time.

Parameter explanation:

• Process

     r:等待执行时间的进程数   b:在不可中断睡眠中的进程数     

• Memory

     swpd：已使用的虚拟内存量        free：空闲内存量        buff：作为缓冲的内存        cache：作缓存的内存     

• Swap

     si：从交换分区写到内存的量        so：从内存写到交换分区的大小     

• Io

     bi：发往块设备的数目(blocks/s)        bo：从块设备接收的块数目 (blocks/s)     

• System

     in：每秒钟的中断次数，包括时钟        cs：每秒的上下文切换次数     

• CPU (% of total CPU time):

     us：运行非内核代码的时间（用户时间，包括nice时间）        sy：运行内核代码的时间（系统时间）        id：空闲时间，早先的Linux2.5.41版本，包含了I/O等待时间        wa：等待IO的时间，早先的Linux2.5.41版本，这个值为0  

Free

Common parameters for the free command:

• The-b,-k,-m,-g is shown in bytes B, Kbytes, megabytes, and gigabytes GB.
• -L display detailed high and low memory statistics
• -C output free number of times

Top, Htop

As described earlier, please click on the 18, Linux command to monitor the server CPU

Sar

The SAR command is still more versatile. Put a portal on here.

Nmon

The 22nd article has been introduced click Nmon

PerfMon Metrics Collector

The 17th article has been introduced, click on PerfMon Metrics Collector

19, the Linux command to monitor the server memory