Differential file and system restores from peers and the cloud

Provided herein are systems and methodologies for highly efficient restoration in a network-based backup system. As described herein, differential-based analysis can be utilized such that a new complete differential is calculated based on signatures and/or other information relating to a given item to be restored prior to retrieving backup data. Based on the differential, only blocks determined to be unique between the current version of the item and the desired version are transmitted, which can then be merged with non-unique locally present blocks to obtain the fully restored version of the item. Further, a hybrid architecture can be employed, wherein signatures and/or data are stored at a global location within a network as well as one or more local peers. Accordingly, a backup client can obtain information necessary for restoration from either the global location or a nearby peer, thus further reducing latency and bandwidth consumption.