Just for curiosity. An example machine: an dedicated amd64 server with the last stable version of FreeBSD and UFS for the partitions.
How much resources consume FreeBSD for each empty jail? I mean, I don't want know what is the resource consumption of a jailed server or whatever, just the overhead of each jail.
I'm especially interested on CPU, memory and IO. For a few jails the overhead is negligible but imagine a server with 100 jails.
Update: I've found a amazing blog post related to this question http://ivoras.sharanet.org/blog/tree/2009-10-20.the-night-of-1000-jails.html