iostat

# iostat
打印系统cpu和输入输出设备（一般指磁盘）的使用情况。一些列的含义可以参考vmstat

## 说明
```
root@Hoiwan-PC:~# iostat --help
Usage: iostat [ options ] [ <interval> [ <count> ] ]
Options are:
[ -c ] [ -d ] [ -h ] [ -k | -m ] [ -N ] [ -s ] [ -t ] [ -V ] [ -x ] [ -y ] [ -z ]
[ -j { ID | LABEL | PATH | UUID | ... } ] [ --human ] [ -o JSON ]
[ [ -H ] -g <group_name> ] [ -p [ <device> [,...] | ALL ] ]
[ <device> [...] | ALL ]
```

### tps
- tps: 每秒对输入输出设备的请求次数

## 示例
### 仅查看cpu
```
iostat -c
```
- 每秒打印一次，共打印两次
```
iostat -c 1 2
```

### 查看所有设备的io
```
iostat -d
```

### 查看指定设备sdb的io扩展信息，会比-p输出更多信息
```
iostat -x sdb
```

### 以json格式输出结果
- os.system()一下做个监控接口？
```
root@Hoiwan-PC:~# iostat -c -o JSON
{"sysstat": {
        "hosts": [
                {
                        "nodename": "Hoiwan-PC",
                        "sysname": "Linux",
                        "release": "5.10.16.3-microsoft-standard-WSL2",
                        "machine": "x86_64",
                        "number-of-cpus": 12,
                        "date": "08/23/2021",
                        "statistics": [
                                {
                                        "avg-cpu":  {"user": 0.03, "nice": 0.01, "system": 0.04, "iowait": 0.01, "steal": 0.00, "idle": 99.92}
                                }
                        ]
                }
        ]
}}
```