US 9,003,135 B2Granted

Efficient allocation and reclamation of thin-provisioned storage

AssigneeInternational Business Machines Corporation

InventorsLeo S. Luan, Frank B. Schmuck

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Abstract

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.

Claims12

Dependent claims

A computer program product for allocating storage space, the computer program product comprising a computer readable storage medium having program code embodied therewith, the program code being executable by a processor to:

maintain 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 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;
and
satisfy a write transaction requiring one or more blocks, including the program code when executed by the processor to:
search the map for a block to satisfy the transaction, the search including one or more blocks selected from the group consisting of:
claimed free, free, and combinations thereof;
satisfy the write transaction with a block having the status value selected from the group consisting of:
claimed free and free, including the processor to prioritize selection of the block with a prioritized selection satisfied with one or more available 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.

7 more elements

A system comprising:

a processing unit in communication with data storage, and in communication with a map;
a functional unit in communication with memory and a processing unit, the functional unit having tools to support data classification, the tools comprising:
a maintenance manager to maintain the map to track a status value of data blocks within a data storage system, the status value selected from the group consisting of:
used, free, and claimed free, wherein a used block is a 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;
and
a transaction manager in communication with the maintenance manager, the transaction manager to satisfy a write transaction requiring one or more blocks including:
searching the map for a block to satisfy the transaction, the search including one or more blocks selected from the group consisting of:
claimed free, free, and combinations thereof;
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 vale of the selected blocks to used following selection the one or more blocks.

8 more elements

Dependencies are inferred from the claim text.

Facts

Application: 13/741,854Filed 15 Jan 2013
Published: US 2014/0201491 A117 Jul 2014
Granted: 7 Apr 2015
Term ends: Not estimatedThe source records don’t support an estimate.

Classification9 codes

G06F 12/023
User address space allocation, e.g. contiguous or non contiguous base addressing: free address space management
G06F 3/0608
Specifically adapted to achieve a particular effect: saving storage space on storage systems
G06F 3/0644
Organizing or formatting or addressing of data: management of space entities, e.g. partitions, extents, pools
G06F 3/0665
Virtualisation aspects: at area level, e.g. provisioning of virtual or logical volumes