Patent ID: 7676510

Claim:
A method for monitoring utilization of a fractionally reserved space on a volume storing application data, comprising: comparing an amount of available overwrite reserve space on the volume to a predetermined overwrite reserve threshold; monitoring a rate of change of an active file system, by a storage server system executing a host application, wherein the monitoring comprises applying a snap-delta function to compare a size of a snapshot with a size of a subsequent snapshot to determine the rate of change at a current time; comparing the rate of change of the active file system to a predetermined rate of change threshold; responsive to the amount of available overwrite reserve space having reached the predetermined overwrite reserve threshold or the rate of change having reached the predetermined rate of change threshold, issuing an alert to an administrator of the server system; responsive to the rate of change not exceeding the rate of change threshold, comparing a space required to create a next snapshot to an available overwrite reserve space on the volume; responsive to the space required to create the next snapshot exceeding the available overwrite reserve space on the volume, causing, by the server system, a deletion of snapshots on the volume; responsive to the space required to create the next snapshot not exceeding the available overwrite reserve space on the volume, writing the next snapshot to the volume.