An apparatus, system, and method are disclosed for allocating non-volatile storage. The storage device may present a logical address, which may exceed a physical storage capacity of the device. The storage device may allocate logical capacity in the logical address space. An allocation request may be allowed when there is sufficient unassigned and/or unallocated logical capacity to satisfy the request. Data may be stored on the non-volatile storage device by requesting physical storage capacity. A physical storage request, such as a storage request or physical storage reservation, when there is sufficient available physical storage capacity to satisfy the request. The device may maintain an index to associate logical identifiers (LIDs) in the logical address space with storage locations on the storage device. This index may be used to make logical capacity allocations and/or to manage physical storage space.