Server and chassis thereof

A chassis, applied to a server comprising a plurality of hard disk drive modules, the chassis comprising:

• a body, comprising an opening and an accommodating space, the hard disk drive modules being accommodated in the accommodating space;
• a partition, disposed at the opening, the partition comprising a first side surface, a second side surface opposite to the first side surface, and at least one flow channel, the first side surface facing the accommodating space, and the flow channel penetrating the first side surface and the second side surface;
• a cover plate, disposed at the opening of the body, the cover plate comprising a plurality of ventilation holes;
• and
• at least one sound deadening structure, disposed between the second side surface of the partition and the cover plate and corresponding to the flow channel, the sound deadening structure comprising a sound absorbing element and a reflecting element, and the reflecting element being disposed on one side surface of the sound absorbing element.