I posted a comment on the blog, but will leave one here as well.<p>In regards to the claim of: "quick instance size scaling with no downtime"<p>I am currently evaluating moving our MySQL server to Amazon's RDS. I liked the sounds of the Multi-AZ RDS as it will greatly decrease downtime. However upon examination I found the following issues:<p>- Changing an instance size results in downtime. Amazon's docs and support say up to 3 minutes.<p>- Any failover can take up to 3 minutes to promote the backup to becoming live.<p>- You will experience downtime during that time<p>- Browsing the support forum, some people complained of it taking more than 3 minutes to failover and in some cases the failover got stuck and they experience a longer downtime until they wrote on the forum and had AWS support manually fix it.<p>So in other words, this is not a silver bullet to making MySQL have 100% uptime. And in fact you will experience "up to 3 minutes" of downtime each week during the maintenance window when a failover will occur (unless they do the failover before the maintenance, which I have not found information on anywhere).