The invention relates to a method and data processing system of managing a storage system, wherein the storage system comprises a first storage space and a second storage space, wherein the first storage space comprises a plurality of files, wherein for each file of said plurality of files at least one attribute is specified, and wherein a policy is assigned to each attribute. The method comprises the steps of determining a policy-specific probability distribution for each policy and of determining a policy-specific probability for each file by use of the policy-specific probability distribution. The method further comprises the step of determining a total probability for each file by use of each policy-specific probability and of moving each file of the plurality of files having a total probability equal to 1 from the first storage space to the second storage space. The method further comprises the step of moving files of the plurality of files having a total probability between 0 to 1 if the storage space used on the first storage space reaches a high threshold value until a low threshold value is reached, wherein the low threshold value and the high threshold value are predetermined.