EFFICIENT SPACE MANAGEMENT FOR HIGH PERFORMANCE WRITABLE SNAPSHOTS

Techniques for providing efficient space management in writable snapshots are disclosed. The techniques include dividing available storage in a files ystem into one or more contiguous allocation unit (AU) chunks. Each AU chunk includes a set of contiguous fixed-size AUs, wherein each AU includes a series of contiguous fixed-size blocks. Each AU chunk also includes a set of contiguous AU mappings, wherein each AU mapping represents a different AU. The techniques also include storing, in a first AU mapping, a first snapshot identifier for a snapshot of the file system to indicate allocation of a first AU represented by the first AU mapping to the snapshot. The techniques further include allocating a first block in the first AU to the snapshot by incrementing, in the first AU mapping, a reference count that tracks a number of blocks in the first AU that are allocated to the snapshot. 公开了用于在可写快照中提供高效空间管理的技术。该技术包括将文件系统中的可用存储分为一个或多个连续的分配单元(AU)组块。每个AU组块包括一组连续的固定大小的AU，其中每个AU包括一系列连续的固定大小的块。每个AU组块还包括一组连续AU映射，其中每个AU映射表示