Generally described, one or more aspects of the present application correspond to techniques for new block store volumes of data from object storage snapshots of an origin volume by creating an intermediary “acceleration pool” of source volumes reserved for supporting the new volume creation process. The source volumes may be prevented from supporting user I/O or computing instances in order to reserve their bandwidth for the transfer of data to the new volumes. In addition, the source volumes can be stored on block store servers to increase the speed with which their data can be transferred to the new volumes. The acceleration pool can be partitioned among users accessing the pool in order to maintain availability even when some users heavily utilize the acceleration pool, with particular source volumes intelligently selected from among a user's partition in order to optimize the speed at which the new volumes are created.