A plurality of computing devices are communicatively coupled to each other via a network, and each of the plurality of computing devices is operably coupled to one or more of a plurality of storage devices. A plurality of failure resilient address spaces are distributed across the plurality of storage devices such that each of the plurality of failure resilient address spaces spans a plurality of the storage devices. The plurality of computing devices maintains metadata that maps each failure resilient address space to one of the plurality of computing devices. The metadata is grouped into buckets. Each bucket is stored in the backend of a computing device. Data may be migrated from an external file system to the plurality of storage devices using inode stubs to represent directories and files of the external file system. As the contents of the external file system are copied, the inode stubs are replaced with real inodes.