公开(公告)号：US10191674B2

公开(公告)日：2019-01-29

申请号：US15130087

申请日：2016-04-15

Applicant: NetApp, Inc.

Inventor： Prahlad Purohit ,  Vidhyalakshmi Venkitakrishnan ,  Anthony J. Li

IPC: G06F3/06 ,  G06F11/30

Abstract: A consistency checker is configured to perform repairs to one or more multi-level dense tree metadata structures shared between volumes managed by a volume layer of a storage input/output (I/O) stack executing on one or more nodes of a cluster. The volumes include a parent volume and a snapshot and/or clone, wherein the snapshot/clone may be represented as an independent volume, and embodied as a respective read-only copy (snapshot) or read-write copy (clone) of the parent volume. Illustratively, the consistency checker verifies and/or fixes (i.e., repairs) on-disk structures of the volume layer, e.g., the shared dense tree, according to a distributed repair procedure that maintains consistency properties across all volumes in a volume family and avoid cyclic repairs made in the context of different volumes sharing the dense tree.

公开(公告)号：US20170300248A1

公开(公告)日：2017-10-19

申请号：US15130087

申请日：2016-04-15

Applicant: NetApp, Inc.

Inventor： Prahlad Purohit ,  Vidhyalakshmi Venkitakrishnan ,  Anthony J. Li

IPC: G06F3/06 ,  G06F17/30

CPC classification number: G06F3/0619 ,  G06F3/0623 ,  G06F3/0659 ,  G06F3/067 ,  G06F11/30

Abstract: A consistency checker is configured to perform repairs to one or more multi-level dense tree metadata structures shared between volumes managed by a volume layer of a storage input/output (I/O) stack executing on one or more nodes of a cluster. The volumes include a parent volume and a snapshot and/or clone, wherein the snapshot/clone may be represented as an independent volume, and embodied as a respective read-only copy (snapshot) or read-write copy (clone) of the parent volume. Illustratively, the consistency checker verifies and/or fixes (i.e., repairs) on-disk structures of the volume layer, e.g., the shared dense tree, according to a distributed repair procedure that maintains consistency properties across all volumes in a volume family and avoid cyclic repairs made in the context of different volumes sharing the dense tree.

公开(公告)号：US20170212919A1

公开(公告)日：2017-07-27

申请号：US15005593

申请日：2016-01-25

Applicant: NetApp, Inc.

Inventor： Anthony J. Li ,  Srinath Krishnamachari ,  Ling Zheng

IPC: G06F17/30 ,  G06F13/40 ,  G06F13/16

CPC classification number: G06F16/2246 ,  G06F13/1668 ,  G06F13/4068 ,  G06F16/2379

Abstract: A bottom-up technique repairs a data structure, e.g., a multi-level dense tree, used to organize volume metadata as metadata entries managed by a volume layer of a storage input/output (I/O) stack executing on one or more nodes of a cluster. The bottom-up repair technique implements a progressive repair algorithm that initially involves traversing each level of the dense tree to determine consistency of metadata entries by ensuring that the entries, e.g., (i) monotonically increase, (ii) do not overlap and (iii), if appropriate, reference (point to) existing entries of a lower level. The technique detects and corrects inconsistencies by, e.g., deleting out-of-order and overlapping entries, and adjusting the range of an index entry to reference the corresponding lower level entry. The technique then examines whether metadata entries at a lower level of the tree are referenced (pointed to) by corresponding index entries in an upper (parent) level. If there is no index entry at the upper level pointing to a lower level entry (i.e., a gap in offset range), the upper level is fixed (repaired) by employing a gap analysis procedure.