The present disclosure describes processing a write command directed to a block-based main storage device, and having a target logical sector and write data. The processing may include writing an address of a physical sector in the main storage device that contains the target logical sector to a header portion of a scratch block stored in a byte-addressable storage. The write data may be written to a slot the scratch block. The scratch block may be committed a scratch block in persistent storage. Subsequent to processing the write command, a write completion response may be signaled to the sender of the write command to indicate to the sender completion of the write command, without having committed the write data to the main storage device. Write data from several write commands may be subsequently committed to the main storage device.