Method and apparatus for data recovery using storage based journaling

a data recovery and storage technology, applied in the field of computer storage, can solve the problems of not being able to service the kind of request in time, no way to and not being able to conveniently recover data at any point in tim

Inactive Publication Date: 2005-01-20
HITACHI LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

The invention is directed to method and apparatus for data recovery and comprises performing a fast recovery mode operation in conjunction with an undo-able recovery mode operation. In the fast recovery mode operation, after-journal entries are applied to a snapshot to

Problems solved by technology

Except for database systems, however, there are no ways to recover data at any point in time.
Also, if an application running on the database system interacts with another application (regardless of whether it is a database system or not), then there i

Method used

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  • Method and apparatus for data recovery using storage based journaling
  • Method and apparatus for data recovery using storage based journaling
  • Method and apparatus for data recovery using storage based journaling

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Embodiment Construction

FIG. 1 is a high level generalized block diagram of an illustrative embodiment of a backup and recovery system according to the present invention. When the system is activated, a snapshot is taken for production data volumes (DVOL) 101. The term “snapshot” in this context conventionally refers to a data image of at the data volume at a given point in time. Depending on system requirements, implementation, and so on, the snapshot can be of the entire data volume, or some portion or portions of the data volume(s); e.g., filesystem(s), file(s), directorie(s), etc. During the normal course of operation of the system in accordance with the invention, a journal entry is made for every write operation issued from the host to the data volumes. As will be discussed below, by applying a series of journal entries to an appropriate snapshot, data can be recovered at any point in time.

The backup and recovery system shown in FIG. 1 includes at least one storage system 100. Though not shown, one ...

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Abstract

A storage system maintains a journal and a snapshot of one or more data volumes. Two journal entry types are maintained, an AFTER journal entry and a BEFORE journal entry. Two modes of data recovery are provided: “fast” recovery and “undo-able” recovery. A combination of both recovery modes allows the user to quickly recover a targeted data state.

Description

BACKGROUND OF THE INVENTION The present invention is related to computer storage and in particular to the recovery of data. Several methods are conventionally used to prevent the loss of data. Typically, data is backed up in a periodic manner (e.g., once a day) by a system administrator. Many systems are commercially available which provide backup and recovery of data; e.g., Veritas NetBackup, Legato / Networker, and so on. Another technique is known as volume shadowing. This technique produces a mirror image of data onto a secondary storage system as it is being written to the primary storage system. Journaling is a backup and restore technique commonly used in database systems. An image of the data to be backed up is taken. Then, as changes are made to the data, a journal of the changes is maintained. Recovery of data is accomplished by applying the journal to an appropriate image to recover data at any point in time. Typical database systems, such as Oracle, can perform journali...

Claims

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Application Information

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IPC IPC(8): G06F12/00
CPCG06F11/1471G06F11/1469G06F2201/84
Inventor YAMAGAMI, KENJI
Owner HITACHI LTD
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