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FIELD

The field relates generally to information processing systems, and more particularly to restoring snapshots using a differential cloud snapshot mechanism.

BACKGROUND

A snapshot is a representation of a state of a system at a particular point in time. For example, storage snapshots can include blocks of data at certain points in time. Snapshots typically provide data protection so that when information is lost due to some failure event, the snapshots provide accessible copies of the data, which allow the data to be restored to a specific point in time if a failure occurs. Snapshots may be stored in chronological order, based on their timestamps.

Users archive data based on one or more policies. For example, data can be moved between storage arrays and one or more cloud storage platforms. Snapshots on a storage array can be transmitted to cloud object storage based on user defined policies. An originating storage array has access to these cloud snapshots, and has the ability to restore any of the snapshots from the cloud storage platform back to a local or remote platform volume of the storage array through a restore mechanism. Existing restore solutions require large amounts of time and processing power to restore the snapshots.

SUMMARY

Illustrative embodiments provide techniques for restoring cloud snapshots using a differential cloud snapshot mechanism, which makes restoration more efficient and less time consuming. For example, in one or more embodiments, a cloud tiering appliance (CTA) restores snapshots starting with snapshots occurring later in time, searches for existing offsets and writes data from offsets not found to exist.

In one embodiment, a method comprises receiving a request to restore a given snapshot of a plurality of snapshots from a cloud storage platform to a storage array. In the method, a first metadata file corresponding to the given snapshot is downloaded from the cloud storage platform, and data corresponding to the given snapshot is written to the storage array. An additional metadata file corresponding to a previous snapshot of the plurality of snapshots with respect to the given snapshot is downloaded. The first metadata file and the additional metadata file are compared to determine whether one or more offsets in the additional metadata file are present in the first metadata file. Data corresponding to any of the one or more offsets determined to be absent from the first metadata file is written to the storage array, and the one or more offsets determined to be absent from the first metadata file are added to the first metadata file.

These and other illustrative embodiments include, without limitation, methods, apparatus, networks, systems and processor-readable storage media.

