Workers operate the conveyor at the intelligent warehouse 'Suning cloud warehouse' of China's retail giant Suning Commerce Group Co in Nanjing, Jiangsu province, Nov 7, 2017. The warehouse can process 1.81 million packages daily and deliver goods in the shortest time of 30 minutes. [Photo/VCG]

For China's online retailers, the upcoming annual Nov 11 Singles Day online shopping spree will be a big test for their logistics systems.

Major players such as JD.com Inc, Suning Commerce Group Co Ltd and Cainiao Network Technology Co Ltd, the smart logistics network of Alibaba Group Holding Ltd, have been putting great efforts in transforming their logistics systems into intelligent ones.

At their warehouses, robots and automatic packaging and sorting systems are deployed to increase efficiency.

Let's check how these intelligent warehouses work.