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In this video, we'll talk about backup strategies.

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A backup is a copy of files, and you should make backups.

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A backup is a copy of files, and you should make backups in case anything is going wrong.

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A full backup is a backup strategy where you will make a copy of all files, but if you

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have lots of files, this may be very inefficient, because if you want to backup tebytes of files,

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that can take days in some cases.

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That is why there is the incremental backup.

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Incremental backup will only backup those files that have changed since the last backup,

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and this is much more efficient.

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The differential backup is another strategy.

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That's the backup of all files that have changed since the last full backup, and it is more

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efficient in a restore than an incremental backup.

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That is because in an incremental backup, if you make a full backup on Sunday, then

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you make a backup of the Monday files, the Tuesday files, the Wednesday files, and so

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on, on every single day.

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So if on Friday you need to restore your original state for Thursday because something has gone

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wrong, you need the Sunday full backup, and the Monday, Tuesday, Wednesday, and Thursday

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incremental backups.

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In a differential backup, the Thursday backup would have all changes since Sunday, and that

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is easier to restore, because then you would only need two backups.

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Alternatively to backups, you can also clone images, and that will make a one-on-one copy

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of a complete device.

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It's not really a backup, but it allows you to get back in case things go wrong.

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Or alternatively, snapshots can be used.

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For example, the LVM Volume Manager can make snapshots to freeze the current state of a

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file system.

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But don't mistake a snapshot for a backup, because a snapshot is always depending on

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the original volume.

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If something bad happens to the original volume, an LVM snapshot will not help you to get back

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to the original state.