High performance virtual machine recovery in the cloud

In this paper, we outline and illustrate concepts that are essential to achieve fast, highly scalable virtual machine planning and failover at the Virtual Machine (VM) level in a data center containing a large number of servers, VMs, and disks. To illustrate the concepts a solution is implemented and analyzed for IBM's Cloud Managed Services enterprise cloud. The solution enables at-failover-time planning, and keeps the recovery time within tight service level agreement (SLA) allowed time budgets via parallelization of recovery activities. The initial serial failover time was reduced for an order of magnitude due to parallel VM restart, and to parallel VM restart combined with parallel storage device remapping.