I read all the comments posted here thus far, and the one thing I don't see is a concern that de-duping, if not done AT the filesystem, would be prohibitively s

I read all the comments posted here thus far, and the one thing I don't see is a concern that de-duping, if not done AT the filesystem, would be prohibitively slow. Am I misguided in thinking that it would be? I mean, I suppose if you implemented it on disk at the server level, retrieving the duped blocks there, I think you're adding latency. I suppose I might be looking at it from the wrong perspective, as there just has to be people using S3 for backups only, for which cost probably does make more sense than speed, but I honestly don't know if that's more the exception or the rule.