DEFERRED REFERENCE COUNT UPDATE TECHNIQUE FOR LOW

专利名称：DEFERRED REFERENCE COUNT UPDATE

TECHNIQUE FOR LOW OVERHEAD VOLUMEMETADATA

发明人：Anshul Pundir,Ashwin Pednekar,Srinath

Krishnamachari,Ling Zheng

申请号：US14484061申请日：20140911

公开号：US20160077744A1公开日：20160317

专利附图：

摘要：A deferred refcount update technique efficiently frees storage space for

metadata (associated with data) to be deleted during a merge operation managed by avolume layer of a node. The metadata is illustratively volume metadata embodied asmappings from logical block addresses (LBAs) of a logical unit (LUN) to extent keysmaintained by an extent store layer of the node. One or more requests to delete (oroverwrite) an LBA range within a LUN may be captured as page keys associated withmetadata pages during the merge operation and the storage space associated withthose metadata pages may be freed in an out-of-band fashion. The page keys of themetadata pages may be persistently recorded in a reference count (refcount) log tothereby allow the merge operation to complete without resolving deletion of the keys. Abatch of page keys may be organized as one or more delete requests and, once themerge completes, the keys may be inserted into the refcount log. Subsequently, adeferred reference count update process may be spawned (instantiated) to walk throughthe page keys stored in the refcount log and delete each key, e.g., from the extent storelayer, independently and out-of-band from the merge operation.

申请人：NETAPP, INC.

地址：Sunnyvale CA US

国籍：US

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