1. A computer-implemented method for social-aware clustering of user data replicas in a large-scale distributed computing system, the method comprising: creating a social graph based on communications between users of the large-scale distributed system, the social graph including nodes representing particular users of the large-scale distributed system, and weighted links between the nodes which represent communications between two users, each weight associated with the respective weighted link determined as a function of communication frequency and types of communication between the two linked users, and the types of communication consuming different amounts of bandwidth and having different latency requirements; identifying, for each of the users, connected datacenters which corresponded to a placement datacenter of the top k other users with whom the respective user communicates most frequently based on the social graph, where k is a predefined number and the placement datacenter is the datacenter where a current user data replica associated with the respective user is stored; identifying, for each of the users, a daily traffic intensity which corresponds to the number of communications sent or received by the respective user each day on a d-day average basis, where d is a predefined number of days; determining, for each of the users and based on the connected datacenters identified for the respective user, a preferred datacenter for storing the current user data replica associated with the respective user; determining, using an optimization model, user replica placement for each of the users that minimizes a distance between the current datacenter storing the current user data replica associated with each of the users and the preferred datacenter for storing the current user data replica associated with each of the users, the optimization model receiving user specific data including the connected datacenters; and updating the datacenter for the current user data replica associated with each of the users to the datacenter determined by the optimization model.