title: S3 high-availability + reliability for backups
body: <p>I did some research on this, but wasn't able to find any substantial answers, so turning to StackOverflow.</p>
  
  <p>How reliable is Amazon's S3 in terms of high-availability and reliability? I realize there are SLAs for it, but what about if a availability zone (AZ) or entire region in AWS goes down?</p>
  
  <p>I checked up Amazon's docs on how S3 is set up. When you try to create a bucket, it says: "When creating a bucket, you can choose a Region to optimize for latency, minimize costs, or address regulatory requirements."</p>
  
  <p>Amazon also says this (<a href="http://aws.amazon.com/articles/1904" rel="noreferrer">source</a>): "Data stored in any given Amazon S3 bucket is replicated across multiple datacenters in a geographical region." </p>
  
  <p>So it does look like S3 data is spread across multiple AZs, but within a region.</p>
  
  <p>What if a region goes down (this has happened before)? Is S3 unavailable then? If so, S3 is not a reliable backup mechanism for restoration when a AWS region goes down, is it?</p>