US 5,765,173 AGranted

High performance backup via selective file saving which can perform incremental backups and exclude files and uses a changed block signature list

AssigneeConnected Corporation

InventorsDavid Cane, David Hirschman

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Abstract

High performance backup of a computer system includes backing up changed portions of files and selectively choosing files for backup. Files are treated as a collection of blocks, and only those blocks which have changed since a previous backup are transmitted to a backup system. Prior to selecting blocks for backup, files are selectively chosen by excluding previously archived files such as commercial software, and excluding other non-critical applications and data based on, inter alia, commonality, modification date and a list of files which are already present in the backup system. Files may also be pre-loaded into a backup system in anticipation of their presence in the computer system to be backed up.

Claims20

Dependent claims

A method for backing up a user system having one or more storage media to a backup system with a backup media, the user system being in communication with the backup system, where at least one previous backup has been made including storing a version T1 target file in the backup system, the method comprising the steps of:

determining which files are present in the backup system;
defining a critical file selection criteria to identify files within the scope of backup;
defining a list of unique file identifier descriptors to specifically identify files already stored on said backup system;
excluding from backup those files which are already stored in the backup system, whereby a file which is common to two or more storage media is backed up only once;
and wherein said excluding is based on comparing files to said list of unique file identifier descriptors;
determining from said user system storage media target files which have changed since the previous backup;
selecting target files which have changed since the previous backup;
eliminating, from said group of target files, entries which are not within the range of files included in said critical file selection criteria;
transmitting the particular selected target file from the user system to the backup system;
and
storing the changed files on the backup system.

8 more elements

A computer system with improved backup and restoration capability comprising:

a user system having one or more storage media with files, said files having attributes and said user system having ability to make changes to said files;
a backup system having backup media, said backup system connected to said user system by a link, said backup system having a version T1 target file and at least one changed block file, said changed block file comprising enumeration of said changes to said files on said storage media, said link having ability to transport said changed block files;
said backup system having a changed block signature list from a previous backup;
a new changed block signature list created during backup, and wherein said new list is compared to said previous list to identify changed blocks;
a forward changed block file created from said identified changed blocks for each selected changed file in said user system wherein said forward changed block files are transmitted from said user system to said backup system;
said version T1 target file updated with said forward changed block files in said backup system to produce a desired version file which is transmitted to the user system during a recovery operation;
a digital signature of the desired version file is computed independently in both said user system and said backup system, and the signatures are compared to verify error-free transfer;
a subset of said files on said user system excluded from backup prior to generating said new changed block signature list, said subset comprised of files for which alternate backup copies exist;
and
a list which indicates files already present in said backup system, copies of said already present files in said user system being excluded from backup.

7 more elements

Dependencies are inferred from the claim text.