title: FIO repeatable buffer fill
body: <p>Is it possible to have a pseudo-random buffer fill pattern using FIO? ie, the fill pattern for a block would incorporate a seed + block number or offset into a pseudo-random fill generator. This way the entire fill data could be 100% repeatable and verifiable, but more varied than the static pattern provided by <code>--verify=pattern</code>.</p>
  
  <p>My guess at the commands would be something like:</p>
  
  <ol>
  <li>Write pseudo-random data out in verifiable manner</li>
  </ol>
  
  <pre><code>fio --filename=/home/test.bin --direct=1 --rw=write --bs=512 --size=1M --name=verifiable_write --verify=psuedo_rand --verify_psuedo_rand_seed=0xdeadbeef --do_verify=0
  </code></pre>
  
  <ol start="2">
  <li>Read back pseudo-random data and verify</li>
  </ol>
  
  <pre><code>fio --filename=/home/test.bin --direct=1 --rw=read --bs=512 --size=1M --name=verify_written_data --verify=psuedo_rand --verify_psuedo_rand_seed=0xdeadbeef --do_verify=1
  </code></pre>
  
  <p>Obviously, I'm making up some options here, but I'm hoping it may get the point across. </p>