A large-scale disaster will affect multiple data centers of an optical cloud network and the contents stored in these data centers should be evacuated for recovery as soon as possible. This paper addresses the problem of data evacuation in a Content-Fragmentation（CF） based optical cloud network before a large-scale disaster. We formulate this problem as a Mixed Integer Linear Programming（MILP） model and develop an efficient Least Delay（LD） based evacuation algorithm. Numerical results show that the performance of proposed LD algorithm is similar to that of the MILP model. In addition

compared to the content replication scheme

the CF based optical cloud network using LD algorithm always takes shorter times to evacuate data.