"Whether you're administering a single, dedicated Web server, or one serving hundreds of hosts, each site's client expects and deserves a certain level of support and service. ..." This article covers mod_throttle, having each site operate under its own user ID, and running several instances of Apache.

"... Thus, if virtual host www.foo.com has a script that writes information to a specific file, it would be fairly easy for a virtual host on the same shared server to read or overwrite the data in that file as well, because all of the hosts run as the same user ID."

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