Abstract: Methods, systems, and apparatus, including computer programs encoded on computer storage media, for determining image search results. One of the methods includes receiving a notification that contents of a first memory page for a first virtual machine on a first host machine are the same as contents of a second memory page for a second virtual machine on a second different host machine. Storage space occupied by the first memory page on the first host machine is deallocated based on the notification. A request from the first virtual machine for the first memory page is received. In response to the request, a copy of contents of the second memory page is obtained from the second host machine.

Abstract: Techniques and systems for managed boot are described. A described technique includes creating, at a server system, a boot image based on one or more user-specified parameters associated with virtual machine booting, providing a first virtual drive that includes the boot image, booting a virtual machine using the boot image on the first virtual drive, and providing a second virtual drive to the virtual machine, where the virtual machine mounts the second virtual drive as a root file system.