man vmstat
FIELD DESCRIPTION FOR VM MODE
Procs
- r: The number of processes waiting for run time.
r 表示运行队列 (就是说多少个进程真的分配到CPU). 当这个值超过了CPU数目, 就会出现CPU瓶颈.
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b: The number of processes in uninterruptible sleep.
Memory
- swpd: the amount of virtual memory used.
- free: the amount of idle memory.
- buff: the amount of memory used as buffers.
- cache: the amount of memory used as cache.
- inact: the amount of inactive memory. (-a option)
- active: the amount of active memory. (-a option)
Swap
- si: Amount of memory swapped in from disk (/s).
- so: Amount of memory swapped to disk (/s).
IO
- bi: Blocks received from a block device (blocks/s).
- bo: Blocks sent to a block device (blocks/s).
System
- in: The number of interrupts per second, including the clock.
- cs: The number of context switches per second.
CPU
- These are percentages of total CPU time.
- us: Time spent running non-kernel code. (user time, including nice time)
- sy: Time spent running kernel code. (system time)
- id: Time spent idle. Prior to Linux 2.5.41, this includes IO-wait time.
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wa: Time spent waiting for IO. Prior to Linux 2.5.41, included in idle.
wa 列显示了IO等待所占用的CPU时间的百分比。这里wa的参考值为30%，如果wa超过30%，说明IO等待严重，这可能是磁盘大量随机访问造成的，也可能磁盘或者磁盘访问控制器的带宽瓶颈造成的(主要是块操作)
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st: Time stolen from a virtual machine. Prior to Linux 2.6.11, unknown.