A mounting assembly includes a chassis, and a plurality of partition panels configured to divide a space in the chassis into a plurality of sub-spaces. A motherboard is attached to the chassis and located below the plurality of partition panels. A plurality of data storage devices is mounted in each of the plurality of sub-spaces. Each of the plurality of data storage devices comprising a casing, at least one drive bracket mounted in the casing, at least one data storage unit mounted in the at least one drive bracket, and a handle pivotably attached to the at least one drive bracket. The handle is rotatable between a locked position, where the at least one drive bracket is immovable from the casing, and a released position, where the at least one drive bracket is released from the casing.