Efficient allocation and reclamation of thin-provisioned storage

摘要

Embodiments of the inventions relate to granular management of data storage blocks in a data storage system. In one aspect, status values are employed to track “used”, “free”, and “claimed free” storage blocks. A storage block having stored data is identified as used, a storage block available to store data is identified as free, and a storage block having previously stored data removed that has not been reclaimed is identified as claimed free. These values are maintained on a map to track each data block within the data storage system. Available claimed free data blocks are prioritized for data block allocation over available free data blocks for efficient storage, including enabling efficient reclamation of data blocks and minimizing data movement needed for reclamation-oriented de-fragmentation.

主权项

1. A method comprising:
maintaining a map for tracking status of data blocks within a data storage system, each block having a status value in the map, the status value selected from the group consisting of: used, free, and claimed free, wherein a used block is a data block with stored data and claimed space, a free block is an unused block without claimed space, and a claimed free block is an unused block with claimed space; responding to a write transaction requiring one or more blocks, including: searching the map for one or more blocks to satisfy the transaction, the one or more blocks selected from the group consisting of: claimed free, free, and combinations thereof; and selecting one or more blocks from the searched map, including prioritizing selection of the block with a primary selection satisfied with one or more claimed free blocks, and a secondary selection satisfied with one or more free blocks; and changing the status value of the selected blocks to used following selection of the one or more blocks.