A computing system comprises a plurality of computing devices. Each computing device includes a plurality of computing modules and a plurality of optical interconnect expansion cards, and each optical interconnect expansion card includes an on-chip optical switch and at least one first optical switching unit. The optical interconnect expansion cards of different computing devices are communicatively connected via optical fibers. At least one computing device is configured as a backup device and remaining computing devices are configured as working devices. In response to a malfunction of one or more working devices, a connection topology of the computing devices is reconfigured by controlling the first optical switching units and/or the on-chip optical switches such that the backup devices equal in number to the malfunctioning working devices are switched to operate as working devices.