In this video, we'll talk about backup strategies.
A backup is a copy of files, and you should make backups.
A backup is a copy of files, and you should make backups in case anything is going wrong.
A full backup is a backup strategy where you will make a copy of all files, but if you
have lots of files, this may be very inefficient, because if you want to backup tebytes of files,
that can take days in some cases.
That is why there is the incremental backup.
Incremental backup will only backup those files that have changed since the last backup,
and this is much more efficient.
The differential backup is another strategy.
That's the backup of all files that have changed since the last full backup, and it is more
efficient in a restore than an incremental backup.
That is because in an incremental backup, if you make a full backup on Sunday, then
you make a backup of the Monday files, the Tuesday files, the Wednesday files, and so
on, on every single day.
So if on Friday you need to restore your original state for Thursday because something has gone
wrong, you need the Sunday full backup, and the Monday, Tuesday, Wednesday, and Thursday
incremental backups.
In a differential backup, the Thursday backup would have all changes since Sunday, and that
is easier to restore, because then you would only need two backups.
Alternatively to backups, you can also clone images, and that will make a one-on-one copy
of a complete device.
It's not really a backup, but it allows you to get back in case things go wrong.
Or alternatively, snapshots can be used.
For example, the LVM Volume Manager can make snapshots to freeze the current state of a
file system.
But don't mistake a snapshot for a backup, because a snapshot is always depending on
the original volume.
If something bad happens to the original volume, an LVM snapshot will not help you to get back
to the original state.