Patent ID: 7536585

Claim:
A computer-implemented method of estimating storage system availability comprising the steps of: modeling a storage system design in operation under a workload by employing a hierarchical model to determine location of retrieval points, the hierarchical model having levels corresponding to each of a primary storage location and a plurality of secondary storage locations, the primary and secondary storage locations serving as sources for retrieval points of successively lower levels of the hierarchical model, and the retrieval points providing sources for primary storage recovery for a plurality of failure scenarios; and for a particular failure scenario: receiving a target recovery time, which is a point-in-time to which restoration of data is desired; finding a secondary storage location from among the plurality of secondary storage locations of a most recent retrieval point relative to the target recovery time that is available for recovery; and determining a recovery time for propagation of the most recent retrieval point from the identified secondary storage location to the primary storage location by determining a recovery path from the identified secondary storage location to the primary storage location and recursively computing a time at which each level in the recovery path is ready to serve as a source for the data.