公开(公告)号：US10108547B2

公开(公告)日：2018-10-23

申请号：US14989392

申请日：2016-01-06

Applicant: NetApp, Inc.

Inventor： Anshul Pundir ,  Ashwin Pednekar ,  Ling Zheng ,  Michael L. Federwisch

IPC: G06F12/12 ,  G06F12/0817 ,  G06F12/0868 ,  G06F12/122 ,  G06F12/123 ,  G06F12/128

Abstract: A technique provides memory efficient caching of metadata managed by a volume layer of a storage input/output stack executing on one or more nodes of a cluster. Efficient caching of the metadata in a memory of a node may be realized through the use of a caching data structure, i.e., a page cache, configured to store a key-value pair, wherein the key is an extent key and the value is a metadata page containing the index entries. The page cache illustratively includes two data structures configured to maintain the properties of Least Recently Used (LRU) and Least Frequently Used (LFU) for the cache. The first data structure is a hash table that stores a dense tree metadata page (value) indexed by the extent key. The second data structure is a recycle queue that controls the metadata page stored in the hash table based on spatial and temporal locality of the page.

公开(公告)号：US20170192892A1

公开(公告)日：2017-07-06

申请号：US14989392

申请日：2016-01-06

Applicant: NetApp, Inc.

Inventor： Anshul Pundir ,  Ashwin Pednekar ,  Ling Zheng ,  Michael L. Federwisch

IPC: G06F12/08

CPC classification number: G06F12/128 ,  G06F3/06 ,  G06F12/0804 ,  G06F12/0873 ,  G06F12/122 ,  G06F12/123 ,  G06F2212/1008 ,  G06F2212/313

Abstract: A technique provides memory efficient caching of metadata managed by a volume layer of a storage input/output stack executing on one or more nodes of a cluster. Efficient caching of the metadata in a memory of a node may be realized through the use of a caching data structure, i.e., a page cache, configured to store a key-value pair, wherein the key is an extent key and the value is a metadata page containing the index entries. The page cache illustratively includes two data structures configured to maintain the properties of Least Recently Used (LRU) and Least Frequently Used (LFU) for the cache. The first data structure is a hash table that stores a dense tree metadata page (value) indexed by the extent key. The second data structure is a recycle queue that controls the metadata page stored in the hash table based on spatial and temporal locality of the page.

公开(公告)号：US20160077744A1

公开(公告)日：2016-03-17

申请号：US14484061

申请日：2014-09-11

Applicant: NETAPP, INC.

Inventor： Anshul Pundir ,  Ashwin Pednekar ,  Srinath Krishnamachari ,  Ling Zheng

IPC: G06F3/06

CPC classification number: G06F3/0608 ,  G06F3/0611 ,  G06F3/0652 ,  G06F3/0655 ,  G06F3/0665 ,  G06F3/067 ,  G06F3/0688

Abstract: A deferred refcount update technique efficiently frees storage space for metadata (associated with data) to be deleted during a merge operation managed by a volume layer of a node. The metadata is illustratively volume metadata embodied as mappings from logical block addresses (LBAs) of a logical unit (LUN) to extent keys maintained by an extent store layer of the node. One or more requests to delete (or overwrite) an LBA range within a LUN may be captured as page keys associated with metadata pages during the merge operation and the storage space associated with those metadata pages may be freed in an out-of-band fashion. The page keys of the metadata pages may be persistently recorded in a reference count (refcount) log to thereby allow the merge operation to complete without resolving deletion of the keys. A batch of page keys may be organized as one or more delete requests and, once the merge completes, the keys may be inserted into the refcount log. Subsequently, a deferred reference count update process may be spawned (instantiated) to walk through the page keys stored in the refcount log and delete each key, e.g., from the extent store layer, independently and out-of-band from the merge operation.

Abstract translation: 延迟重新计费更新技术有效地释放了在由节点的卷层管理的合并操作期间要删除的元数据（与数据相关联）的存储空间。 元数据示例性地是体现为从逻辑单元（LUN）的逻辑块地址（LBA）到由节点的扩展区存储层维护的扩展密钥的映射的卷元数据。 删除（或覆盖）LUN中的LBA范围的一个或多个请求可以被捕获为在合并操作期间与元数据页相关联的页面键，并且与那些元数据页相关联的存储空间可以以带外方式释放 。 元数据页面的页面键可以被持久地记录在引用计数（引用计数）日志中，从而允许合并操作完成而不解决键的删除。 一批页面键可以被组织为一个或多个删除请求，并且一旦合并完成，则可以将密钥插入到引用计数日志中。 随后，可以产生（实例化）延迟引用计数更新处理以遍历存储在引用计数日志中的页面密钥，并且例如从扩展存储层中删除每个密钥，从合并操作中独立地进行带外删除。