A method of operating a storage unit having non-volatile random-access memory (NVRAM) and solid-state memory is provided. The method includes transferring contents of the NVRAM to the solid-state memory, in response to detecting a power loss. The method includes during the transferring, having each of a plurality of channels in parallel, reading one or more of a plurality of logical unit numbers (LUNs) each corresponding to a portion of the NVRAM, performing an XOR of data of each of the one or more of the plurality of LUNs with data of a preceding LUN, and writing results of the XOR to the solid-state memory.