title: What is exactly meant by "fire and forget" write in MongoDB
body: <p>MongoDB has a write mechanism of <code>fire and forget</code>. But does this guarantee that my writes will be written to disk eventually? So if i have a statement like this(in pymongo)</p>
  
  <pre><code>collection.insert(doc)     #not passing safe=True
  </code></pre>
  
  <p>I understand that my write in above statement will not immediately reach the disk but is there a guarantee that it would ever reach the disk(maybe the next day or a week later) or can it get lost and never come back. My application needs dont want the writes to be done synchronously but they want the writes to happen even if its hours later.</p>