International Business Machines Corporation
Dynamically adjusting the number of replicas of a file according to the probability that the file will be accessed within a distributed file system

Abstract:

In a data storage system with a number of replicas of a file set to one or more replicas, a timer is set to track a time since a last access to the file. Responsive to the timer matching a first timer window threshold, the timer is reset to count to a second timer window threshold and a number of replicas of the file are automatically reduced within the data storage system, wherein the probability that the file will be accessed prior to the first timer window threshold is greater than the probability that the file will be accessed after the first timer window threshold. Responsive to the timer matching the second timer window threshold, the timer is reset to count to a third timer window threshold. Responsive to receiving a read access prior to the timer reaching the third timer window threshold, the number of replicas of the file is increased and the timer reset to count to the second timer window threshold.