Tracking storage capacity usage by snapshot lineages using metadata in a multi-level tree structure

Patent metadata

Field	Value
Publication number	US-2021286535-A1
Application number	US-202016814446-A
Country	US
Kind code	A1
Filing date	Mar 10, 2020
Priority date	Mar 10, 2020
Publication date	Sep 16, 2021
Grant date	—

Abstract

An apparatus comprises a processing device configured to identify a snapshot lineage comprising snapshots of a storage volume and to maintain, for the snapshot lineage, a multi-level tree structure comprising (i) a first level comprising a primary volume object representing the storage volume and snapshot volume objects representing the snapshots of the storage volume and (ii) additional levels comprising data objects, where the primary and snapshot volume objects comprise pointers to the data objects, the data objects comprising data of the storage volume and snapshots. The processing device is also configured to determine storage capacity usage by the snapshot lineage based on a collective size of the data objects pointed to by the primary and snapshot volume objects, to store the determined storage capacity usage as metadata associated with the primary volume object, and to dynamically update the metadata responsive to changes in the snapshot lineage.

First claim

What is claimed is:

1 . An apparatus comprising:
at least one processing device comprising a processor coupled to a memory; the at least one processing device being configured:
to identify a snapshot lineage comprising one or more snapshots of a storage volume comprising data stored on one or more storage devices of a storage system;
to maintain, for the snapshot lineage, a multi-level tree structure comprising (i) a first level comprising a primary volume object representing the storage volume and one or more snapshot volume objects representing the one or more snapshots of the storage volume and (ii) one or more additional levels comprising a plurality of data objects, each of the primary volume object and the one or more snapshot volume objects comprising pointers to one or more of the plurality of data objects, the plurality of data objects comprising respective portions of data of the storage volume and the one or more snapshots of the storage volume;
to determine storage capacity usage by the snapshot lineage based at least in part on a collective size of the plurality of data objects pointed to by the primary volume object and the one or more snapshot volume objects in the multi-level tree structure;
to store the determined storage capacity usage of the snapshot lineage as metadata associated with the primary volume object; and
to dynamically update the metadata associated with the primary volume object responsive to changes in the snapshot lineage to track storage capacity usage by the snapshot lineage.

2 . The apparatus of claim 1 wherein at least a given one of the plurality of data objects is shared by the storage volume and a given one of the one or more snapshots of the storage volume.

3 . The apparatus of claim 1 wherein the storage volume comprises one of:
at least one of the one or more storage devices of the storage system;
a given logical unit provided by at least one of the one or more storage devices;
a consistency group comprising a set of two or more logical units provided by at least one of the one or more storage devices; and
an access-restricted storage group comprising a set of two or more logical units provided by at least one of the one or more storage devices where access to the storage group is limited to one or more designated host devices.

4 . The apparatus of claim 1 wherein the snapshot lineage comprises a local snapshot lineage stored on at least one of the one or more storage devices of the storage system and the multi-level tree structure comprises a local multi-level tree structure comprising a local primary volume object representing a current version of the storage volume.

5 . The apparatus of claim 4 wherein the snapshot lineage further comprises at least one cloud snapshot lineage stored on cloud storage of at least one cloud external to the storage system, wherein the metadata associated with the local primary volume object representing the current version of the storage volume comprises first metadata characterizing storage capacity usage of the local snapshot lineage and second metadata characterizing storage capacity usage of the at least one cloud snapshot lineage.

6 . The apparatus of claim 5 wherein the at least one cloud snapshot lineage comprises a first cloud snapshot lineage stored on first cloud storage of a first cloud external to the storage system and a second cloud snapshot lineage stored on second cloud storage of a second cloud external to the storage system, and wherein the second metadata comprises a first portion characterizing storage capacity usage of the first cloud snapshot lineage and a second portion characterizing storage capacity usage of the second cloud snapshot lineage.

7 . The apparatus of claim 1 wherein the snapshot lineage comprises at least one cloud snapshot lineage stored on cloud storage of at least one cloud external to the storage system, the multi-level tree structure comprises a cloud multi-level tree structure comprising a cloud primary volume object representing a most recent snapshot of the storage volume stored on the cloud storage of the at least one cloud external to the storage system, and the one or more snapshot volume objects represent one or more previous snapshots of the storage volume stored on the cloud storage of the at least one cloud external to the storage system.

8 . The apparatus of claim 1 wherein dynamically updating the metadata associated with the primary volume object is responsive to at least one of:
changes in data of the storage volume;
responsive to generation of a new snapshot of the storage volume in the snapshot lineage; and
responsive to removing one or more snapshots from the snapshot lineage.

9 . The apparatus of claim 1 wherein the one or more additional levels of the multi-level tree structure comprise:
a second level comprising a subset of the plurality of data objects representing region objects; and
a third level comprising a subset of the plurality of data objects representing page objects, the page objects comprising leaf nodes of the multi-level tree structure.

10 . The apparatus of claim 9 wherein the at least one processing device is further configured to generate a new snapshot of the storage volume, wherein generating the new snapshot of the storage volume comprises creating a new snapshot volume object in the multi-level tree structure as a copy of the primary volume object.

11 . The apparatus of claim 9 wherein dynamically updating the metadata associated with the primary volume object comprises, responsive to modifying data of the storage volume represented by one or more existing region objects and one or more existing page objects in the multi-level tree structure, updating the multi-level tree structure by:
writing one or more new region objects and one or more new page objects comprising the modified data; and
updating one or more pointers of the primary volume object from the one or more existing region objects to the one or more new region objects.

12 . The apparatus of claim 11 wherein dynamically updating the metadata associated with the primary volume object and updating the one or more pointers of the primary volume object are performed as part of a single atomic commit transaction.

13 . The apparatus of claim 11 wherein updating the multi-level tree structure further comprises:
removing ones of the one or more existing region objects not referenced by at least one of the one or more snapshot volume objects; and
removing ones of the one or more existing page objects not referenced by the one or more new region objects and remaining ones of the one or more existing region objects.

14 . The apparatus of claim 1 wherein the at least one processing device is part of the storage system.

15 . A computer program product comprising a non-transitory processor-readable storage medium having stored therein program code of one or more software programs, wherein the program code when executed by at least one processing device causes the at least one processing device to perform steps of:
identifying a snapshot lineage comprising one or more snapshots of a storage volume comprising data stored on one or more storage devices of a storage system; maintaining, for the snapshot lineage, a multi-level tree structure comprising (i) a first level comprising a primary volume object representing the storage volume and one or more snapshot volume objects representing the one or more snapshots of the storage volume and (ii) one or more additional levels comprising a plurality of data objects, each of the primary volume object and the one

Assignees

• Emc Ip Holding Co Llc

Inventors

• Aldred Mark
• King David

Classifications

• G06F11/3409

  for performance assessment · CPC title

• G06F11/1464

  for networked environments · CPC title

• G06F11/1469

  Backup restoration techniques · CPC title

• G06F11/1451

  by selection of backup contents · CPC title

• G06F11/3466

  Performance evaluation by tracing or monitoring · CPC title