A computing environment includes a home site and a cache site with nonhomogeneous thin-provisioned storage configurations. A file management system updates files stored at the cache site. Each updated file has an updated file size and a pre-update file size. When a resynchronization is needed between the cache site and the home site, for example due to an extended communication failure, the storage requirement changes for the updated files are calculated and a notification is sent to the home site. The notification identifies the updated files and the storage requirement changes. The home site sends a reply to the cache site. The reply identifies which files are approved for immediate processing. The cache site transfers resynchronization data for the approved files to the home site, and delays transferring resynchronization data for the unapproved files until subsequent replies from the home site indicate that the previously unapproved files are now approved.