Browse Prior Art Database

In-Place Update Of A Full Backup Image During Subsequent Incremental Backup Operation(s)

IP.com Disclosure Number: IPCOM000213430D
Publication Date: 2011-Dec-14
Document File: 3 page(s) / 27K

Publishing Venue

The IP.com Prior Art Database

Abstract

Disclosed is a method to conserve database storage space through maintaining a single up-to-date backup image every time an incremental backup is requested by the user.

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In-Place Update Of A Full Backup Image During Subsequent Incremental Backup Operation(s)

Backup and restore are fundamental components of applications such as databases and many storage-intensive subsystems (such subsystems are collectively referred to as applications in this disclosure). Most applications support the notion of a full backup and incremental backup. A full backup copies an entire dataset and creates a backup

image on the specified target location. An incremental backup copies only the modified

dataset since the last full or incremental backup. The drawbacks of existing solutions areexemplified in the following scenario:

Assumptions

• Business has backup policy that includes a full backup every Sunday and an incremental backup every day Monday through Saturday


• The initial size of the dataset is 1000 pages


• Every day 5% of the dataset is changing


• For simplicity, assume that the total size of the dataset is not increasing


• Typically, every backup image will have a constant space overhead required by metadata for backup itself; in this disclosure assume that overhead to be 0.

Table: Storage consumed by a backup policy that includes a full backup every Sunday and an incremental backup every day Monday through Saturday

As demonstrated above, the total storage consumed by this backup policy by the end of the week will be 1300 pages, which is 30% larger than the dataset size. For a very large dataset (e.g., databases are commonly in the order of terabytes) the overhead from this additional space consumed by incremental backup can be a constraint. The alternative, performing a full backup daily, would solve the space constraint but may be

impossible to complete in a timely manner within maintenance windows, even if the organization could afford a maintenance window in an increasingly 24x7 environment.

There also exist third-party tools that merge one or more incremental backup images

with a full backup image, but this merge is a post-processing of these images and thus suffers from the higher space consumption described above. The advantage of such an approach is that during recovery, user only has to deal with a single merged backup image, making recovery easier and faster.

The invention provides an environment in which storage savings are accomplished by

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maintaining a single up-to-date backup image every time an incremental backup is requested by the user. The incremental backup makes in-place updates to the existing full backup image with respect to the incremental changes. In addition to significant storage savings, this approach lends itself to ease in administration and is less error prone since the user has to deal with/restore a single backup image. Finally, the process of restore itself is faster since a single image is used for the restore.

A high-level overview of the process may be as follows:

1. The starting point for the process is a regular full backup image where each...