Backup

What is Backup ???

Backup is activity of copying file/database. It is procedure that you can implement to protect your important data. Called as "Restoring them".

Why we need to backup ?

1. If your hard drive could fail
2. your file could become corrupted
3. Laptop may be lost or stolen 
4. A virus or other malicious program could harm your data 

Where to backup ?

• Box Cloud Storage -File and folders can be uploaded quickly and can be accessed from anywhere on any device. 

• USB Flash Drive/Pen-drive - It small and portable that can be reused many time. 

• CDs and DVDs

• External Drives - External drives can be stored at an offsite location to protect them from physical damage that might be caused by a fire or other disaster. External drives tend to be the most expensive option for backing up your data.

When to Backup ?

You need to backing up your data after you have created enough new files or made enough changes to existing file that it would be difficult to recreate them. 

3.1 Full Backup

•        A complete backup of everything you want to backup.
•        Is starting point for all other backups and contains all the data in the folders and files that are selected to be backed up.
•        Should be performed before any major planned changes to a system.

Advantage	Disadvantage
Provide quickest restore time	It takes longer time to accomplish
Stored in a single file	Required the most storage space

3.2 Differential Backup

•  Differential backup contains all files that have changed since the last full backup.With differential backups, one full backup is done first and subsequent  
•    Backup runs are the changes made since the last full backup.

Restoring	Backing Up
- Restoring a differential backup is slower than restoring from full backup.	- Backing up is faster than a full backup.
- Restoring a differential backup is faster than restoring an incremental backup.	- Backing up is slower than an incremental backup.

Example of Full Backup

3.3 Imaging Backup / Mirror Backup

-         Imaging backup is a backup process for a computer that create a copy of the operating system and all the data associated with it, including the system state and application configurations. The backup is saved as a single file that is called an image.

Advantage	Disadvantage
All information can be collected in a single pass, providing and updated bare metal restore.	Some vendors are incorporting data reduction technologies such as data deduplication.

3.4 Incremental Backup

- Incremental backup stores all files changed since the last backup

- Backup of every file on a file system which has changed since the last backup

Monday	Full Backup ( 10GB )
Tuesday		2GB
Wednesday			1GB
Thursday				2GB

TOTAL AMOUNT IN STORAGE 10 GB + 2 GB + 1 GB + 2 GB = 15 GB

- An incremental backup is the fastest backup

- The result is a much faster backup then a full backup for each backup run

- Requires the least storage space on the backup media

- However, incremental backups also require the longest time and many tapes to restore

- Incremental backups should be used only in environments where backup time or backup                  storage media are extremely constrained

Advantages	Disadvantages
It is the fastest backup type since it only backs-up increments	Full restore is slow compared to other backup types (you need the first full backup and all increments since then)
Saves storage space compared to other types and each backup increment can store a different version for a file/folder	To restore the latest version of an individual file the increment that contains it must be found first

For More Information - https://www.youtube.com/watch?v=TpdOwIufJ5k by Sewdenim