[Linux] Monitor Linux系統的各種資源狀態

• 計算網路卡的流量
  
  #cat /sys/class/net/$nic_dev/statistics/$file
  
  $file :
  rx_bytes : 目前已接收的bytes
  tx_bytes : 目前已傳輸的bytes
  rx_packets : 目前已接收的packets
  tx_packets : 目前已傳輸的packets


• 計算網路卡的流量 - Script
  
  #!/bin/sh
  
  INTERVAL=1
  
  nic=$1
  
  while true
  do
      R1=`cat /sys/class/net/$nic/statistics/rx_bytes`
      T1=`cat /sys/class/net/$nic/statistics/tx_bytes`
      sleep $INTERVAL
      R2=`cat /sys/class/net/$nic/statistics/rx_bytes`
      T2=`cat /sys/class/net/$nic/statistics/tx_bytes`
  
      RKBPS=$((($R2 - $R1) / 1024))
      TKBPS=$((($T2 - $T1) / 1024))
  
      echo "TX $nic: $TKBPS kB/s RX $nic: $RKBPS kB/s"
   
  done


• 計算IO的讀寫量
  #cat /proc/PID/io
  
  欄位:
  rchar: number of bytes the process read, using any read-like system call (from files, pipes, tty...).
  wchar: number of bytes the process wrote using any write-like system call.
  syscr: number of read-like system call invocations that the process performed.
  syscr: number of write-like system call invocations that the process performed.
  read_bytes: number of bytes the process directly read from disk.
  write_bytes: number of bytes the process originally dirtied in the page-cache (assuming they will go to disk later).
  cancelled_write_bytes: number of bytes the process "un-dirtied" - e.g. using an "ftruncate" call that truncated pages from the page-cache.