Provided is a method of completing object IOs, the method including receiving a first set of object IOs for a target storage device, dispatching the first set of object IOs to a first buffer of a first zone, the first buffer being configured to function as a first log buffer, concatenating the first set of object IOs to form a first object group in the first buffer, logging the first object group to a log device, modifying a function of the first buffer from the first log buffer to a first flush buffer, and transferring the first object group to the target storage device.