Solaris 10 will have "zones" which are similar to jails, plus will have a "container" setup where you have a zone located inside a container, and can configure RAM usage, CPU, number of simultaneous processes that can be run, etc. for each zone. If a zone takes up more than the configured amount of RAM, it will have its least active pages swapped out.
Rebooting a zone will take a few seconds. You will be able to have up to 8191 zones per machine.
