Resource recovery for checkpoint-based high-availability in a virtualized environment

Abstract

A computer-implemented method provides checkpoint high-available for an application in a virtualized environment with reduced network demands. An application executes on a primary host machine comprising a first virtual machine. A virtualization module receives a designation from the application of a portion of the memory of the first virtual machine as purgeable memory, wherein the purgeable memory can be reconstructed by the application when the purgeable memory is unavailable. Changes are tracked to a processor state and to a remaining portion that is not purgeable memory and the changes are periodically forwarded at checkpoints to a secondary host machine. In response to an occurrence of a failure condition on the first virtual machine, the secondary host machine is signaled to continue execution of the application by using the forwarded changes to the remaining portion of the memory and by reconstructing the purgeable memory.

Description

PRIORITY CLAIM[0001]The present application is a continuation of U.S. patent application Ser. No. 13 / 253,519, titled “Resource Recovery for Checkpoint-Based High-Availability in a Virtualized Environment,” filed on Oct. 5, 2011, the contents of which is incorporated herein by reference in its entirety.BACKGROUND[0002]1. Technical Field[0003]The present disclosure relates to a virtualized environment for a data processing system, and more particularly to resource recovery on a secondary host machine in the event of a failure condition of a virtual machine operating on a primary host machine.[0004]2. Description of the Related Art[0005]Checkpoint-based high-availability is a technique whereby a virtual machine running on a host machine (the “Primary host”) regularly (e.g., every 25 ms) mirrors its Central Processing Unit (CPU) and memory state onto another host machine (the “Secondary Host”). This mirroring process involves: 1. tracking changes to the memory and processor state of the...

AI Technical Summary

Benefits of technology

The patent describes a method for making sure an application running in a virtual machine is always available. This is done by forwarding changes in the virtual machine to a separate virtual machine. By doing this, the amount of data that needs to be forwarded is reduced, and the memory of the original virtual machine is not wasted. This helps to recover resources quickly in case of failures.

Problems solved by technology

One of the key performance bottlenecks in this process is the rate at which pages of modified memory must be transferred from the primary host to the secondary host during execution.

The cost of this approach is therefore at least twofold.

First, the first write to any page in a given checkpoint interval (the space between two checkpoints) causes a fault that must be handled before the workload can resume.

Second, the page must be transferred to the secondary host, which consumes network bandwidth.

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