SNPdisk: An efficient para-virtualization snapshot mechanism for virtual disks in private clouds

Using virtualization techniques, a cloud administrator can consolidate, distribute, and manage computing resources through a network from a central console. Existing open source virtual machine monitors, such as Xen, do not support virtual disk snapshot and rollback, which is important for clouds, especially for virtual cloud storage and computing resource management. Although traditional snapshot technologies may be directly applied to virtual cloud storage, they are inefficient and not fully reliable. Most seriously, the techniques impose limitations on the cloud environments. In this article, we present SNPdisk (snapshot disk), a para-virtualization snapshot mechanism, which uses a novel sparse tree scheme to implement reliable and efficient snapshots. Experiments with a prototype system demonstrate its high performance; it is especially useful for private clouds.