System and method for restoring data on demand for instant volume restoration

The art which restores the data of the dispersion volume which sets one or more Brock pointers in file system structure to ABSENT (absent), carries out marking, and consists of fetching suitable data from an alternative place by on demand one is indicated. The client-data access demand to a local storage system makes restoration of the data from an external storage start if needed. Data can be restored as a background process by using a demand generator, searching for dispersion entire volume, and restoring absent Brock's data. The pump module for adjusting access of a demand generator is also indicated. After all the data is restored, volume has [no] data locally and the volume is no longer dispersion volume.