Types of Backup

There are quite a number of backup types and terms used when it comes to backups of your digital content. This is a compilation of the most common types of backup with a brief explanation of their meaning, common examples, advantages and disadvantages of each backup type.

Full Backup

Full backup is a method of backup where all the files and folders selected for the backup will be backed up.  It is commonly used as an initial or first backup followed with subsequent incremental ordifferential backups. After several incremental or differential backups, it is common to start over with a fresh full backup again.

Some also like to do full backups for all backup runs typically for smaller folders or projects that do not occupy too much storage space.

Example of a Full Backup

You setup a full backup job or task to be done every night from Monday to Friday. Assume you do your initial backup on Monday, this first backup will contain your entire list of files and folders in your backup job. On Tuesday, at the next backup run, the entire list of files and folders will be copied again. On Wednesday, the entire list of files and folders will be copied again and the cycle continues like this. At each backup run, all files designated in the backup job will be backed up again. This includes files and folders that have not changed.

Advantages

• Restores are fast and easy to manage as the entire list of files and folders are in one backup set.
• Easy to maintain and restore different versions.

Disadvantages

• Backups can take very long as each file is backed up again every time the full backup is run.
• Consumes the most storage space compared to incremental and differential backups. The exact same files are be stored repeatedly resulting in inefficient use of storage.

Incremental backup

Incremental backup is a backup of all changes made since the last backup. The last backup can be a full backup or simply the last incremental backup. With incremental backups, one full backup is done first and subsequent backup runs are just the changed files and new files added since the last backup.

Example of An Incremental Backup

You setup an Incremental backup job or task to be done every night from Monday to Friday. Assume you perform your first backup on Monday. This first backup will be a full backup since you haven’t done any backups prior to this. On Tuesday, the incremental backup will only backup the files that have changed since Monday and any new files added to the backup folders.  On Wednesday only the changes and new files since Tuesdays backup will be copied. The cycle continues this way.

Advantages

• Much faster backups
• Efficient use of storage space as files are not duplicated. Much less storage space used compared to running full backups and even differential backups.

Disadvantages

• Restores are slower than with a full backup and differential backups.
• Restores are a little more complicated. All backup sets (first full backup and all incremental backups) are needed to perform a restore.

Differential backup

Differential backups fall in the middle between full backups and incremental backup. A differential backup is a backup of all changes made 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.The result is a much faster backup then a full backup for each backup run. Storage space used is less than a full backup but more then with Incremental backups. Restores are slower than with a full backup but usually faster then with Incremental backups

Example of A Differential Backup

You setup a differential backup job or task to be done every night from Monday to Friday. Assume you perform your first backup on Monday. This first backup will be a full backup since you haven’t done any backups prior to this. On Tuesday, the differential backup will only backup the files that have changed since Monday and any new files added to the backup folders.  On Wednesday, the files changed and files added since Monday’s full backup will be copied again. While Wednesday’s backup does not include the files from the first full backup, it still contains the files backed up on Tuesday.

Advantages

• Much faster backups then full backups
• More efficient use of storage space then full backups since only files changed since the last full backup will be copied on each differential backup run.
• Faster restores than incremental backups

Disadvantages

• Backups are slower then incremental backups
• Not as efficient use of storage space as compared to incremental backups. All files added or edited after the initial full backup will be duplicated again with each subsequent differential backup.
• Restores are slower than with full backups.
• Restores are a little more complicated then full backups but simpler than incremental backups. Only the full backup set and the last differential backup are needed to perform a restore.

Mirror Backup

Mirror backups are as the name suggests a mirror of the source being backed up. With mirror backups, when a file in the source is deleted, that file is eventually also deleted in the mirror backup.Because of this, mirror backups should be used with caution as a file that is deleted by accident, sabotage or through a virus may also cause that same file in mirror to be deleted as well. Some do not consider a mirror to be a backup.

Many online backup services offer a mirror backup with a 30 day delete. This means that when you delete a file on your source, that file is kept on the storage server for at least 30 days before it is eventually deleted.  This helps strike a balance offering a level of safety while not allowing the backups to keep growing since online storage can be relatively expensive.

Many backup software utilities do provide support for mirror backups.

Advantages

• The backup is clean and does not contain old and obsolete files

Disadvantages

• There is a chance that files in the source deleted accidentally, by sabotage or through a virus may also be deleted from the backup mirror.

Full PC Backup or Full Computer Backup

Full PC backup of full computer backup typically involves backing up entire images of the computers hard drives rather than individual files and folders. The drive image is like a snapshot of the drive. It may be stored compressed or uncompressed.

With other file backups, only the user’s document, pictures, videos and music files can be restored while the operating system, programs etc need to be reinstalled from is source download or disc media.

With the full PC backup however, you can restore the hard drives to its exact state when the backup was done. Hence, not only can the documents, pictures, videos and audio files be restored but the operating system, hardware drivers, system files, registry, programs, emails etc. In other words, a full PC backup can restore a crashed computer to its exact state at the time the backup was made.

Full PC backups are sometimes called “Drive Image Backups”

Examples Full PC Backup

There are several vendors that offer full PC backup and restore software. These softwares have to be installed on the computer being backed up.

Typically one of the first things you need to do before you start the backup is to create a bootable rescue disk or DVD.  When a computer has crashed but still has a workable hard disk, this rescue disk will be used to boot up the computer with minimum features to start the restore of the hard disk.  Once the restore is complete, the computer can then boot up on its own primary hard disk again and would have all its files, programs, database settings etc just as it was at the time of the backup.

Advantages

• A crashed computer can be restored in minutes with all programs databases emails etc intact. No need to install the operating system, programs and perform settings etc.
• Ideal backup solution for a hard drive failure.

Disadvantages

• May not be able to restore on a completely new computer with a different motherboard, CPU, Display adapters, sound card etc.
• Any problems that were present on the computer (like viruses, or mis-configured drivers, unused programs etc) at the time of the backup may still be present after a full restore.

Local Backup

A local backup is any backup where the storage medium is kept close at hand.  Typically, the storage medium is plugged in directly to the source computer being backed up or is connected through a local area network to the source being backed up.

Examples of Local Backups

• Internal hard drive
• External hard drive (desktop or portable)
• Optical drives like CDs, DVDs and Blue Ray discs
• Solid state drives like USB Thumb drives or Flash Drives
• Network Attached Storage (NAS)
• Backup to a shared folder on another computer over the network
• Magnetic tape drives

Advantages

• Offers good protection from hard drive failures, virus attacks, accidental deletes and deliberate employee sabotage on the source data.
• Very fast backup and very fast restore.
• Storage cost can be very cheap when the right storage medium is used like external hard drives
• Data transfer cost to the storage medium can be negligible or very cheap

• Since the backups are stored close by, they are very conveniently obtained whenever needed for backups and restore.
• Full internal control over the backup storage media and the security of the data on it. There is no need to entrust the storage media to third parties.

Disadvantages

• Since the backup is stored close by to the source, it does not offer good protections against theft, fire, flood, earthquakes and other natural disasters. When the source is damaged by any of these circumstances, there’s a good chance the backup will be also damaged.

Offsite Backup

Any backup where the backup storage medium is kept at a different geographic location from the source is known as an offsite backup. The backup may be done locally at first on the usual storage devices but once the storage medium is brought to another location, it becomes an offsite backup.

Examples Of Offsite Backups

• When the backup drives of the office computers are taken home by the Administrator or Manager for safekeeping.
• When the backup drive is kept at another branch office at another site or building.
•  When the backup drive is kept at a bank safe deposit box.
• When the backup is sent across the Internet or network connection to a storage facility or data centre in another city. (Also known as online backup or remote backup)

Offsite backups offer all of the same protection as local backups with added protection against theft, fire, floods, earthquakes, hurricanes and other natural disasters. Putting the backup media in the next room as the source would not be considered an offsite backup as the backup does not offer this added protection.

Advantages

• Offers additional protection when compared to local backup such as protection from theft, fire, flood, earthquakes, hurricanes and more.

Disadvantages

• Except for online backups, it requires more due diligence to bring the storage media to the offsite location.
• May cost more as people usually need to rotate between several storage devices. For example when keeping in a bank deposit box, people usually use 2 or 3 hard drives and rotate between them. So at least one drive will be in storage at any time while the other is removed to perform the backup.
• Because of increased handling of the storage devices, the risk of damaging delicate hard disk is higher. (does not apply to online storage)

NOTE : With faster Internet connections and more and more online backup providers coming up with competitive packages, the practice of bringing home a hard disk or bringing it to the bank is becoming less attractive.

Online Backup

An online backup is a backup done on an ongoing basis to a storage medium that is always connected to the source being backed up. The term “online” refers to the storage device or facility being always connected. Typically the storage medium or facility is located offsite and connected to the backup source by a network or Internet connection.  It does not involve human intervention to plug in drives and storage media for backups to run.

Many commercial data centers now offer this as a subscription service to consumers. The storage data centers are located away from the source being backed up and the data is sent from the source to the storage center securely over the Internet.

Typically a client application is installed on the source computer being backed up.  Users can define what folders and files they want to backup and at one times of the day they want the backups to run. The data may be compressed and encrypted before being sent over the Internet to the storage data center.

The storage facility is a commercial data center located away from the source computers being backed up. Typically they are built to certain fire and earthquake safety specifications.  They have higher security standards with CCTV and round the clock monitoring.  They typically have backup generators to deal with grid power outages and the facility is temperature controlled. Data is not just stored in one physical media but replicated across several devices.  These facilities are usually serviced by multiple redundant Internet connection so there is no single point of failure to bring the service down.

Examples of Online Backups

There are many commercial service providers offering this as a subscription service. Some market it under the term Remote Backup or Cloud Backup

Advantages

• Offers the best protection against fires, theft and natural disasters.
• Because data is replicated across several storage media, the risk of data loss from hardware failure is very low.
• Because backups are frequent or continuous, data loss is very minimal compared to other backups that are run less frequently.
• Because it is online, it requires little human or manual interaction after it is setup.

Disadvantages

• Is a more expensive option then local backups.
• Initial or first backups can be a slow process spanning a few days or weeks depending on Internet connection speed and the amount of data backed up.
• Can be slow to restore.

Remote Backup

Remote backups are a form of offsite backup with a difference being that you can access, restore or administer the backups while located at your source location or other physical location. The term “remote” refers to the ability to control or administer the backups from another location.
You do not need to be physically present at the backup storage facility to access the backups.

Putting your backup hard drive at your bank safe deposit box would not be considered a remote backup. You cannot administer or access it without making a trip to the bank. The term “remote backup” is often used loosely and interchangeably with “online backup” and “cloud backup”.

Examples of Remote Backup

• Subscription backup services provided by commercial data centers.
• Backup to an offsite FTP Server.

Advantages

• Much better protection from natural disasters than local backups.
• Easier administration as it does not need a physical trip to the offsite backup location.

Disadvantages

• More expensive then local backups
• Can take longer to backup and restore than local backups

Cloud Backup

Cloud backup is a term often used loosely and interchangeably with Online Backup and Remote Backup.  This is a type of backup where data is backed up to a storage server or facility connected to the source via the Internet. With the proper login credentials, that backup can then be accessed securely from any other computer with an Internet connection. The term “cloud” refers to the backup storage facility being accessible from the Internet.

Examples of Cloud Backup

• Subscription backup services provided by commercial data centers.
• Backup to an offsite FTP Server over the Internet

Advantages

• Since this is an offsite backup, it offers protection from fire, floods, earth quakes and other natural disasters.
• Able to easily connect and access the backup with just an Internet connection.
• Data is replicated across several storage devices and usually serviced by multiple internet connections so the system is not at the mercy of a single point of failure.
• When the service is provided by a good commercial data center, service is managed and protection is un-paralleled.

Disadvantages

• More expensive then local backups
• Can take longer to backup and restore

FTP Backup

This is a kind of backup where the backup is done via the File Transfer Protocol (FTP) over the Internet to an FTP Server. Typically the FTP Server is located in a commercial data center away from the source data being backed up. When the FTP server is located at a different location, this is another form of offsite backup.

Examples of FTP Backup

Some commercial web hosting providers also provide an FTP server when you sign up for a web hosting service. Some providers do allow you to use this for backups but note that not all of these service providers allow you to use the FTP server to backup your local computer files. Some of these service providers have been known to even delete these backups without warning. Hence you must verify with your service provider before you start to do FTP backups on these servers.

Once you have organized an FTP server that you can use, you need to install a backup software utility that supports an FTP backup. You would need to specify the web address of your FTP server (like ftp://your-ftp-server/) , your login username and password so the backup utility can execute the backup.

Advantages

• Since this is an offsite backup, it offers protection from fire, floods, earth quakes and other natural disasters.
• Able to easily connect and access the backup with just an Internet connection.

Disadvantages

• More expensive then local backups
• Can take longer to backup and restore. Backup ane restore times are dependant to the Internet connection