公开(公告)号：US10339132B2

公开(公告)日：2019-07-02

申请号：US14795066

申请日：2015-07-09

Applicant: NetApp, Inc.

Inventor： Pinkesh Zaveri ,  Mandar Naik ,  Edward D. McClanahan

IPC: G06F16/23

Abstract: A flow control technique prevents exhaustion of storage resources in an exactly once semantics (EOS) system of a storage input/output stack executing on a node of a cluster. An EOS server may service transactions sent by an EOS client and issue replies with results to the EOS client. In order to replay the transactions during normal operation after recovery from a crash, the EOS server persistently stores the transactions in the storage resources until an acknowledgement of completion is received from the EOS client for each pending transaction. The EOS client may issue a checkpoint acknowledgement, e.g., as a prune record, after a periodic interval that marks the completion of all pending transactions issued prior to the record. The EOS server need only log the prune record (rather than each pending transaction) to thereby prevent exhaustion of the storage resources, while also minimizing logging overhead of the server. In response to the crash and during replay of the transactions, the EOS server may employ the prune records to ignore those transactions that have already been acknowledged by the EOS client, thereby reducing time required for replay of the transactions.

公开(公告)号：US20170011062A1

公开(公告)日：2017-01-12

申请号：US14795066

申请日：2015-07-09

Applicant: NetApp, Inc.

Inventor： Pinkesh Zaveri ,  Mandar Naik ,  Edward D. McClanahan

IPC: G06F17/30

CPC classification number: G06F16/2379 ,  G06F16/2358

Abstract: A flow control technique prevents exhaustion of storage resources in an exactly once semantics (EOS) system of a storage input/output stack executing on a node of a cluster. An EOS server may service transactions sent by an EOS client and issue replies with results to the EOS client. In order to replay the transactions during normal operation after recovery from a crash, the EOS server persistently stores the transactions in the storage resources until an acknowledgement of completion is received from the EOS client for each pending transaction. The EOS client may issue a checkpoint acknowledgement, e.g., as a prune record, after a periodic interval that marks the completion of all pending transactions issued prior to the record. The EOS server need only log the prune record (rather than each pending transaction) to thereby prevent exhaustion of the storage resources, while also minimizing logging overhead of the server. In response to the crash and during replay of the transactions, the EOS server may employ the prune records to ignore those transactions that have already been acknowledged by the EOS client, thereby reducing time required for replay of the transactions.

Abstract translation: 流控制技术防止在簇的节点上执行的存储输入/输出堆栈的精确一次语义（EOS）系统中的存储资源的耗尽。 EOS服务器可以为EOS客户端发送的事务提供服务，并向EOS客户端发送结果回复。 为了在崩溃恢复后的正常操作中重播事务，EOS服务器将事务永久存储在存储资源中，直到从EOS客户端收到每个待处理事务的完成确认。 EOS客户端可以在标记完成在记录之前发出的所有待处理事务的周期性间隔之后发出检查点确认，例如作为剪枝记录。 EOS服务器只需要记录剪枝记录（而不是每个待处理的事务），从而防止存储资源的耗尽，同时也减少服务器的日志开销。 响应于事务的崩溃和重播期间，EOS服务器可以使用修剪记录来忽略已经被EOS客户端确认的那些事务，从而减少重播事务所需的时间。

公开(公告)号：US09846539B2

公开(公告)日：2017-12-19

申请号：US15004101

申请日：2016-01-22

Applicant: NetApp, Inc.

Inventor： Sriranjani Babu ,  Mandar Naik ,  Srinath Krishnamachari ,  Dhaval Patel

IPC: G06F12/02 ,  G06F3/06 ,  G06F11/14

CPC classification number: G06F3/0608 ,  G06F3/0641 ,  G06F3/0655 ,  G06F3/0665 ,  G06F3/0685 ,  G06F3/0688 ,  G06F11/1407 ,  G06F11/1435

Abstract: A technique recovers from a low space condition associated with storage space reserved in an extent store to accommodate write requests received from a host and associated metadata managed by a layered file system of a storage input/output (I/O) stack executing on one or more nodes of a cluster. The write requests, including user data, are persistently recorded on non-volatile random access memory (NVRAM) prior to returning an acknowledgement to the host by a persistence layer of the storage I/O stack. Volume metadata managed by a volume layer of the layered file system is embodied as mappings from logical block addresses (LBAs) of a logical unit (LUN) accessible by the host to extent keys maintained by an extent store layer of the layered file system. Extent store metadata managed by the extent store layer is embodied as mappings from the extent keys to the storage locations of the extents on storage devices of storage arrays coupled to the nodes of the cluster. The space recovery technique accounts for storage space consumed in the extent store by user operations, i.e., write operations for the user data stored on the NVRAM at the persistence layer as well as the associated volume and extent store metadata, to ensure that the user data and associated metadata can be safely and reliably persisted in the extent store even during a low space condition.