A method, system, and computer program product for file storage defragmentation on a cluster of nodes. The method for self-governed, contention-aware scheduling of file defragmentation operations commences by calculating a score for candidate files of a storage volume, where the score is based on a fragmentation severity value. The process proceeds to determine an amount of contention for access to a candidate file (e.g., by accessing the candidate file to record the amount of time it takes to obtain access). If the fragmentation severity value and the amount of contention suggestion a benefit from defragmentation, then the method initiating defragmentation operations on the candidate file. The method delays for a calculated wait time before performing a second defragmentation operation. Real-time monitors are used to determine when the contention is too high or when system utilization is too high. Only files that have ever been opened are considered candidates for defragmentation.