A system includes a rack and one or more server systems mounted in the rack. A server system includes a chassis with one or more arrays of devices in the chassis. Each array includes mass storage devices and a server device mounted in the array within the chassis of the server system. The server device occupies no more than an equivalent volume of space in the chassis as one of the mass storage devices. A set of mass storage devices of an array and the server device of the array form a logical node, and a server system may include multiple logical nodes in the same chassis. Each array of devices may be located in a sled that can move into and out of the chassis of the server system.