Linux system Monitoring

Virtual Memory Statistics: Vmstat

In layman's words, virtual memory:

Now the operating system is multi-channel batch processing, that is, there are many tasks in memory, then there is a problem, memory enough? Certainly not enough, according to the local principle, only the part of the program loaded into memory, run to the required code is to go to the disk to replace the memory, this is the virtual memory.        Probably say the process, the operating system to execute an instruction, according to the address of this directive in a table to see this instruction in the memory, if in memory to calculate the real memory address, if not in memory in the table to obtain the external memory block of this instruction and to move this command to memory (interrupt), and then And then you can happily execute the program.

Let's start with a command.

　　

Chunking to introduce

Procs

R: Number of processes in the running queue (I don't know why we add this here)

B: Number of processes waiting for IO

Memory

SWPD: Use virtual memory size, if more than 0 means memory is not enough, this time to see if there is a memory leak or to see if you want to upgrade the memory

Free: idle physical memory size

Buff: The amount of memory used as a buffer

Cache: The amount of memory used as a buffer

Swap:

Si: Writes from swap to memory size per second, disk into memory

So: Memory size per second written to swap, with memory tuned to disk

If these two values are greater than 1, the memory is not enough

Io:

BI: Number of blocks read per second

Bo: Number of blocks written per second

The larger these two values are, the greater the value of the IO, and so on.

System:

In: Number of interrupts per second, including clock interrupts

CS: Number of context switches per second

These two values indicate how long the kernel consumes the CPU

Cpu:

US: User space

SY: Kernel space

ID: Idle

Wa:io wait

　　

　　

Linux system Monitoring