Saturday, August 1, 2009

selecting the type of backup operation

the backup utility provides five types of backup operations that define what data is backed up, such as only those files that have changed since the last backup.

some backup types use backup markers also known as archive attributes, which mark file as having changed. when file changes, an attribute is set on the file that indicates that the file has changed since the last backup. when you backup the file, this clears or resets the attributes.

Normal

during a normal backup, all selected files and folders are backed up. a normal backup does not rely on markers to determine which files to backup. during a normal backup any existing marks are cleared and each file is marked as having been backed up. normal backups spped up the restore process because the backup files are the most current and you do not need to restore multiple backup jobs.

Copy

during a copy backup, all selected files and folders are backed up. it neither looks for no clears markers. if you do not want to clear markers and effect other backup types, use a copy backup, for example use a copy backup between a normal and an incremental backup to create an archival snapshot of network data.

Incremental

during incremental backup, only selected files and folders that have a marker are backed up, and then the backup clears markers. because an incremental backup clears markers, if you did two consecutive incremental backups on a file and nothing changed in the file, the file would not be backed up the second time.

Differential

during a differential backup, only selected files and folders that have a marker are backed up, but the backup does not clear markers. because a differential backup does not clear markers, if you did two consecutive differential backups on a file and nothing changed in the file, the entire file would be backed up each time.

Daily

during a daily backup, all selected files and folders that have changed during the day are backed up. this backup neither looks for nor clears markers. if you want to backup all files and folders that change during the day, use daily backup.

System state data

system state data includes various critical operating system files, folders and databases. for all windows 2003 computers, system state data includes the operating system boot files, the registry, and the COM+ class registration database. on a windows 2003 server computer that has certificate services installed, system state data also includes the certificate serivces database.

finally on a windows 2003 server that is a domain controller, system state data also includes the active directory data store and the contents of the SYSVOL folder.

The archive attribute

the archive attribute is a marker that the operating system automatically assigns to all files and folders when they are first installed created. depending on the backup type, backup programs remove the archive attribute from a file or folder to indicate that the file or folder has been backed up. if a file or folder is modified after it is backed up, the operating system reassigns the archive attribute to it.

Using backup to perform a backup

windows 2003 ships with a backup program called backup. backup is a basic tape backup program that gives you full capability to backup and restore a windows 2003 computer, including user data on local and network drives, and system state data on the local computer.

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