Design and Implementation of File Layout in Blue Whale Cluster File System

File layout,which manages the mapping relationship between logical offset of file and physical address of storage device,is important for a file system.The commonly used triple-indirect and extent-based layouts are not fit for cluster file systems that use stripe to improve performance,such like BWFS.A novel fixed-length extent-based layout was presented and improved as power-length extent-based layout especially for small-size files.The presented layout effectively absorbs the direct-mapping advantage of triple-indirect layout and efficient mapping,less layout space waste advantages of extent-based layout.Test results show that the presented layout is efficiently fit for BWFS.The layout can also be used in other file systems which use stripe technology.