title: Synchronize 2 GCS buckets schedulled
body: <p>Didn't find answer for this, so:
  I have my production Google Cloud Storage bucket A, and also a bucket B that I keep only for backup of A, and it's actually in another different Google project. I need that:</p>
  
  <ul>
  <li><p>I can make this sync operation once and have it run forever periodically, instead of having to run or trigger it again and again. With periodically I mean daily or weekly, I don't need more often than that.</p></li>
  <li><p>Contents go directly from A to B, to avoid the extra cost of transfering everything through a third machine (like my laptop or a ComputeEngine box).</p></li>
  <li><p>Preferably it would imply copying only new contents and changes, since 90% will be the same from last sync.</p></li>
  </ul>
  
  <p>My questions:</p>
  
  <ol>
  <li><p>I think that Storage Transfer Service is the best option but I'd like someone who knows better to confirm. Any better option?</p></li>
  <li><p>Is it true that Storage Transfer Service meets my second requirement and gsutil doesn't? It seems so, but then I'm surprised they don't mention it when the docs say "Should you use gsutil or Cloud Storage Transfer Service?" (<a href="https://cloud.google.com/storage/transfer/" rel="nofollow noreferrer">https://cloud.google.com/storage/transfer/</a>)</p></li>
  </ol>
  
  <p>Thanks a lot in advance.</p>