1. A system comprising: a processor; a memory coupled with the processor; a storage system coupled with the memory; and a computer-readable medium embodying a program operable to cause the processor to perform operations comprising: defining multiple metadata blocks in a persistent storage, the multiple metadata blocks comprising information that links a virtual address space to the storage system, where the defining includes, for at least one of the multiple metadata blocks, determining multiple output addresses corresponding to the storage system, and writing the multiple output addresses and an identifier corresponding to the multiple metadata blocks in a metadata block in the persistent storage.