A file system may employ an enhanced or performance-adjusted allocation scheme when storing data to multiple storage devices. A file system may monitor one or more performance characteristics of storage devices. The file system may, in response to storage requests, select one or more of the storage devices for storing data associated storage requests based on differences among the respective monitored performance characteristics for the storage devices. Additionally, the file system may determine an allocation pattern for storing data to the storage devices and may modify the determined allocation pattern based on a detected change in the monitored performance characteristics of the storage devices. Further, the file system may store data based on both the allocation pattern and on data characteristics associated with a data storage request. The file system may also incorporate input specifying either new performance characteristics or a new allocation pattern.