System and method for performing backups of a multi-class file system are described. In one embodiment, more recently modified data may be assigned and/or migrated to higher storage classes and less recently modified data may be migrated at time intervals to lower storage classes in the multi-class file system. Backups of each of the storage classes may be performed at time intervals. In one embodiment, the backups may be image-based backups of the storage devices in the storage classes. In one embodiment, the lower storage classes may include one or more read-only storage classes including less-recently modified data that are backed up less frequently than higher storage classes including more-recently modified data. In one embodiment, files migrated to lower storage class(es) may be compressed.