Using virtual disks for disk system checkpointing

摘要

A scheme is presented for storing data on disks in such a way that a checkpoint can easily be taken across several disks connected to different processors in a distributed or parallel computer. A checkpoint can be used to restore the entire disk system to a known state after one or more of the disks or processors fails. When a failure occurs, the disk system is restored to its state at the current checkpoint. The scheme allows significant saving in disk space by requiring that only the data modified since the last checkpoint be copied. The checkpointing algorithm is presented as part of the invention. The invention allows checkpointing of disk space independently of the use of the disk space, for example, in a file system.