linux 可观测性

名称:

​ vmstat - 报告虚拟内存（statistics）统计数据

命令语法：

​ vmstat [options] [delay [count]]

命令描述：

​ 报告进程、内存、分页、块IO、traps、磁盘和cpu活动的信息。命令的第一行展示了自最后一次启动以来指标的平均值

参数：

​ [delay] 更新指标的间隔时长（秒）

​ [count] 总过更新的次数。如果指定了[delay] 而不指定[count]则表示无限次

​ -a 展示活跃和非活跃的内存 举例： vmstat -a

​ -m 展示slatinfo信息 举例：vmstat -m

[root@ecs-ali ~]# vmstat
procs -----------memory---------- ---swap-- -----io---- -system-- ------cpu-----
 r  b   swpd   free   buff  cache   si   so    bi    bo   in   cs us sy id wa st
 1  0      0  91848 119812 1080588    0    0  1553   931   10    8  5  3 88  4  0

   Procs
       r: The number of runnable processes (running or waiting for run time).
       b: 在等待i/o完成的进程数

   Memory
       swpd: 交换分区的使用量
       free: 空闲物理内存量
       buff: buffer使用量
       cache: cache使用量
       inact: 非活跃的内存量.  (-a option)
       active: 活跃内存量.  (-a option)

   Swap
       si: 从磁盘交换出的内存量 (/s).
       so: 交换到磁盘的内存量(/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.
       wa: Time spent waiting for IO.  Prior to Linux 2.5.41, included in idle.
       st: Time stolen from a virtual machine.  Prior to Linux 2.6.11, unknown.

对于内存应该关注si 和 so ,正常情况下物理内存应该可以容纳进程所需数据，因此不存在数据在交换分区的换入换出。

   /proc/meminfo
   /proc/stat
   /proc/*/stat

磁盘调度

[root@ceph-mon2 docker]# cat /sys/block/sda/queue/scheduler
noop [deadline] cfq