Книга: Windows Server 2012 R2 Storage, Security, & Networking Pocket Consultant

Basic types of backup

Basic types of backup

There are many techniques for backing up files. The techniques you use depend on the type of data you’re backing up, how convenient you want the recovery process to be, and more.

If you view the properties of a file or directory in File Explorer, you’ll find an attribute called archive. You often use this attribute to determine whether a file or directory should be backed up. If the attribute is on, the file or directory might need to be backed up. You can perform the following basic types of backups:

? Normal/full backups All files that have been selected are backed up, regardless of the archive attribute’s setting. When a file is backed up, the archive attribute is cleared. If the file is later modified, this attribute is set, indicating that the file needs to be backed up.

? Copy backups All files that have been selected are backed up, regardless of the archive attribute’s setting. Unlike in a normal backup, the archive attribute on files isn’t modified. This enables you to perform other types of backups on the files at a later date.

? Differential backups Designed to create backup copies of files that have changed since the last normal backup. The presence of the archive attribute indicates that the file has been modified, and only files with this attribute set are backed up. However, the archive attribute on files isn’t modified. This enables you to perform other types of backups on the files at a later date.

? Incremental backups Designed to create backups of files that have changed since the most recent normal or incremental backup. The presence of the archive attribute indicates that the file has been modified, and only files with this attribute set are backed up. When a file is backed up, the archive attribute is cleared. If the file is later modified, this attribute is set, indicating that the file needs to be backed up.

? Daily backups Designed to back up files by using the modification date on the file itself. If a file has been modified on the same day as the backup, the file will be backed up. This technique doesn’t change the archive attribute of files.

As part of your backup operations, you’ll probably want to perform full backups on a weekly basis and supplement this with daily, differential, or incremental backups. You might also want to create an extended backup set for monthly and quarterly backups that includes additional files that aren’t being backed up regularly.

TIP You’ll often find that weeks or months go by before anyone notices that a file or data source is missing. This doesn’t mean the file isn’t important. Although some types of data aren’t used often, they’re still needed. So don’t forget that you might also want to create extra sets of backups for monthly or quarterly periods, or for both periods, to ensure that you can recover historical data.

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