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A method of enabling File-level restore from Image-level backup

IP.com Disclosure Number: IPCOM000199284D
Publication Date: 2010-Aug-30
Document File: 5 page(s) / 85K

Publishing Venue

The IP.com Prior Art Database

Abstract

Disclosed is a mechanism for enabling virtual block device mapping by combining the meta data from catalog and the storage media from data repository, which allow a backup system to provide individual file-level restore from image-level backup.

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A method of enabling File -

files need to be read and transferred during the restore.

In conclusion, this new method enables doing file-level restore from image-level backup of the traditional backup system, which means to achieve both high backup speed and restore speed at the same time.

Here's a snapshot of how the proposed VDM works:

The VDM simulates the virtual disk image based on the below data:
1) The backup catalog (database), that records which image has been backed up and stored in which backup media. The catalog is created and maintained by backup system.
2) Backup media, that stores the data backed from the client. Various kinds of backup media can be used for backup, including file and tape.

A disk image is essentially a block device. During an Image-level backup, the backup system copies thedata from the client disks to the backup media, and builds the catalog to describe the relationship between the client disk and the backup media.

Table.1 is an example the catalog of a full image backup of Disk1. In this example, Disk1 contains 1000 blocks, and was copied onto 3 segments on 2 tape volumes.

DiskName

 Start block

1

-level restore from Image

level restore from Image -

-level backup

level backup

This disclosure proposed a mechanism, Virtual Disk Mapper (VDM), which can be used to simulate a virtual disk image (RAW block device) based on the catalog and media created during backup. This virtual disk image can be mounted locally on server or exported to client, and client can simply mount the exported disk image with appropriate file system format and restore only the files they need.

With this proposed method, users can:
1) Apply image backup to ensure high backup speed. The Image backup function exists in most popular backup systems.
2) Used VDM described above to get a virtual disk image exported from backup system, and restore the files at will.

Note that only the selected

Number of

blocks

Backup Media

Name

Start

Address

Disk1 0 500 Tape01 500 Disk1 500 400 Tape01 1000

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Disk1 900 100 Tape02 200
Table 1

The Virtual Disk Mapper (VDM) maps the data on tape volumes or other backup media to a virtual disk.

A file read/write request against...