fioコマンドのrwオプション

fioコマンドの公式マニュアルから引用

rw=str Type of io pattern. Accepted values are:

      read        Sequential reads
      write       Sequential writes
      randwrite   Random writes
      randread    Random reads
      rw,readwrite    Sequential mixed reads and writes
      randrw      Random mixed reads and writes
      trimwrite   Mixed trims and writes. Blocks will be
              trimmed first, then written to.

  For the mixed io types, the default is to split them 50/50.
  For certain types of io the result may still be skewed a bit,
  since the speed may be different. It is possible to specify
  a number of IO's to do before getting a new offset, this is
  done by appending a ':<nr>' to the end of the string given.
  For a random read, it would look like 'rw=randread:8' for
  passing in an offset modifier with a value of 8. If the
  suffix is used with a sequential IO pattern, then the value
  specified will be added to the generated offset for each IO.
  For instance, using rw=write:4k will skip 4k for every
  write. It turns sequential IO into sequential IO with holes.
  See the 'rw_sequencer' option.

タイプ一覧

type	原文	解釈	設定時注意点
read	Sequential reads	連続したブロックの読み取り
write	Sequential writes	連続したブロックへの書き込み
randwrite	Random writes	ランダムなブロック位置の読み取り
randread	Random reads	ランダムなブロック位置への書き込み
rw,readwrite	Sequential mixed reads and writes	連続したブロックへの読み込みと書き込み
randrw	Random mixed reads and writes	ランダムなブロック位置への読み込みと書き込み	rwmixreadやrwmixwriteパラメータと組み合わせて、読み書きの割合を調整する。
trimwrite	Mixed trims and writes. Blocks will be trimmed first, then written to.	？？

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