Detailed Ntbackup Five ways to backup (next)

Iv. differential Backups (differental backup)

A differential backup is relative to a full backup and is also a file that has changed since the last full backup. Sounds like an incremental backup, and the big difference is that a differential backup does not erase the file's archive tag after the backup action completes, and the incremental backup does.

We still have the example of backing up 5 colleague logs in the above section. For example, Monday, we have a full backup of all the logs, Tuesday, we make a differential backup, that is, only to back up the modified content. However, the a property of the file is not modified at this time. Wednesday, continued differential backup, except for the day of backup modification, together with the Sunday modified files will also be backed up together. Analogy What about the time of recovery? The first thing to do is to restore the first full backup, and then just restore the last differential backup file because it already contains all the previously modified parts. Let's use a table to illustrate this process:

(Please note the difference from the above picture)

In fact, a differential backup is a bit more time-consuming than an incremental backup because each time you back up the content that was last backed up, in contrast, incremental and full backups are the most important combination of backups, saving time and effort.

V. Daily backups (everyday Backup)

Daily backups, that is, to back up only modified content on the day. How do you understand it? For example, everyone will understand.

1, January 1, I created 2 text files, A.txt and B.txt, press F5 in A, this time will automatically enter the day's date and time.

2, then the system time to January 2, open B.txt and press the F5, will automatically enter the day's date and time, two text file creation date is certainly different.

3, I put the system time back to January 1, and then select these two files for their daily backup.

4, after the backup, in order to verify the backup effect. We restore this file, you will find only A.txt, and there will be no B.txt. Because the current date on the day of the backup is January 1.

So, daily backups take time to determine whether those files are backed up or not. That is, if the modification time and backup operation time are the same, then the backup, otherwise ignored. So, if we turn the time to number 4th and use the daily backup, you'll find nothing in the restore, even if you make sure that all the files are selected at the time of the backup, the daily backup does not clear the archive mark.

The above is Ntbackup five kinds of backup type explanation, hope to your work and study helpful, thank you.

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