One aspect of the invention is a method for restoring data, which for
example, includes receiving a request for at least a portion of the data.
This example also includes creating a directory entry for the data in a
virtual file system, and allocating storage space for the data. This
example further includes initializing a block virtualization indicator to
a value indicating that the data is not available. This example
additionally includes writing a subset of the data to the storage space,
and changing the block virtualization indicator to a value indicating
that the data is available.