Most Resource-Efficient Way to Deploy Multiple Rails Apps on a Single Server

I have a Virtual Dedicated Server that I use to host small websites that aren't large enough to justify their own dedicated slice. I am a Rails developer and am currently using an Ubuntu/Nginx/Mongrel Cluster/SQLite stack to deploy these applications.

I feel that the memory being consumed by each Mongrel instance is too high. I am wondering what the recommended way to serve these applications is to keep resource usage to a minimum. I have heard that Mongrel开发者_StackOverflow中文版 is no longer recommended in favor of Passenger. I have continued using Mongrel, though, because I feel that it is more lightweight. This may be a complete misperception on my part, though.

Any ideas?

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Having Passenger + Enterprise RoR may help with the memory footprint (and probably performance).