Differential snapshot system and use method thereof

Abstract

The invention discloses a differential snapshot system and a use method thereof. The system comprises a snapshot module and a thin provisioning module. The snapshot module is used for maintaining the dependency relationship of a source volume and a snapshot volume, snapshooting a strategy semantic expression and managing snapshot metadata. The thin provisioning module comprises a resource management submodule used for achieving the resource management functions on snapshots, and the functions comprise resource allocating, resource mapping and resource recovering. The snapshot module and the thin provisioning module are in communication through an interface of a general block layer. The snapshot module sends a data demand or a resource management command to the thin provisioning module to achieve communication. According to the system, semantic snapshooting and physical resource managing are uncoupled, the storage resources can be distributed according to needs, the processing logic of copy on write, redirect of write and write anywhere can be achieved, and the effective utilization rate of the snapshot resources is increased.

Description

technical field [0001] The invention relates to the field of information technology, in particular to a differential snapshot technology in the storage field. Background technique [0002] The Storage Networking Industry Association (SNIA) divides snapshots into two categories according to implementation technologies: full-copy snapshots and differential-copy snapshots. Compared with the full copy snapshot, the differential snapshot technology has outstanding advantages such as low time overhead and high space utilization, so the differential snapshot technology is widely used in the industry. Currently, there are three implementations of differential snapshot technology, namely copy on write (COW, Copy On Write), redirect on write (ROW, Redirect Of Write), and write anywhere (WA, Write Anywhere), to meet the needs of different instances. [0003] Copy-on-write, the principle is as follows figure 1 As shown, before the source volume data is overwritten for the first time a...

AI Technical Summary

Problems solved by technology

Resource map management and maintenance add complexity to the snapshot system

[0009] Second, snapshot implementation technology is coupled with resource management methods. According to the definition of the Storage Network Industry Association, copy-on-write or redirect-on-write are resource reservation methods, which do not support on-demand allocation.

As a result, it is difficult to improve the effective utilization of resources in these two implementations.

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