I'm no expert in cloud computing - I've spent a fair bit of time researching it and various providers but am yet to get any hands-on experience with it. From what I've read about AWS and auto-scaling EC2 instances though, it seems as though each instance should be completely decoupled from all other instances. i.e. If content is uploaded to the web server's local filesystem from a custom CMS backend then that content won't be available if subsequently requested from a different web server in the auto-scaling group. Is that right?
I met with a representative of our existing hosting provider recently and he was claiming that it isn't a problem that our legacy CMS system is highly dependent on having a local filesystem. He said that all web servers, regardless of how many, would be kept as exact duplicates so I shouldn't notice any difference compared to our existing setup of a single dedicated server. This smells a little too much like bull fecal-matter to me...should I be skeptical about this? I'm a little worried because my (non-technical) boss who ultimately makes the decisions is all for signing up to this cloud solution because it won't require any extra work.
I'm sure that they must at least be able to provide this, otherwise they wouldn't be attempting to sell it to us. But at what cost? It sounds as though each web server will always need to be checking the other web server(s) for new static content, which to me sounds like unwanted overhead that'll slow things down.
I'd really appreciate it if somebody could clear this up to me. I'm all for switching to AWS and using S3+CloudFront for all static content, but that isn't looking very likely to happen at the moment.