A differential snapshot system and its application method

Abstract

The invention discloses a differential snapshot system and its usage method. The system comprises: a snapshot module, used for maintaining the dependencies between source volumes and snapshot volumes, snapshot policy semantics, and managing snapshot metadata; a thin configuration module, the thin configuration The module has a resource management sub-module, which is used to realize the resource management function of the snapshot, which includes resource allocation, resource mapping, and resource recovery; the snapshot module communicates with the thin provisioning module through a common block layer interface, and the snapshot module communicates with the The thin provisioning module communicates by sending data requests or resource management commands. The system decouples snapshot semantics from physical resource management, can allocate storage resources on demand, and can implement three processing logics: copy-on-write, redirect-on-write, and write-anywhere, improving the effective utilization of snapshot resources.

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 OfWrite), 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 af...

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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