Backups

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This material was developed with funding from the National Science Foundation under Grant # DUE 1601612

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Design Data

Tablet Data

In information systems, a data backup is a copy of organization data taken and stored elsewhere. In the case of a data loss event, the backup is used to restore the original data. Devices including smart phones, tablets, laptops, workstations, virtual machines, servers and other systems that create, collect, modify and process information need to be backed up.

Laptop Data

Backup

Smart Phone Data

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Server or Database Data

Data Backups

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Item-level backups include collections of information that are items. Files stored in a file system are the most common type of item. Another type of item is an object in an object storage system. Object storage systems include Amazon S3, Azure Blob, or Google Cloud Storage. Even though object storage systems are replicated to multiple locations for data resiliency, it is not necessarily designed to survive an attack that deletes the object itself. The object deletion, whether accidental or malicious, will be replicated across all copies. Backups can be scheduled daily, weekly, monthly or continuously as data is modified. Backups are essential in restoring a system following a disaster or restoring small numbers of files or portions of files after they have been accidentally lost or corrupted. The most challenging aspect of the backup process is organizing the storage space and managing the procedure. Data storage requirements can be high, but there are many different storage options available for storing backups. These devices can provide geopgraphic redundancy, data security, and portability.

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Selected Folders & Files

External Media

Entire Systems

Item-level Backups

Data Modified Since Last Backup

Backup Storage

A

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When the user goes to back up his files, the backup utility will include only those files and folders that have the archive attribute turned on.

The archive bit is a file attribute. Various backup utilities use the archive bit to determine which files to back up and which files to skip. The archive bit turns on when a user creates and saves a new file or modifies an existing file.

Archive Bit

A full backup is a full copy of the entire data set. The Storage Network Industry Association (SNIA) defines it as "A backup in which all of a defined set of data objects are copied, regardless of whether they have been modified since the last backup". Organizations typically perform a full backup on a periodic basis because it requires more storage space and takes more time to complete. A full backup also uses the most network and server resources. The full backup provides a faster data recovery and simplified restore processing. The archive attribute is reset.

FULL Backup

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Full Backup

Click each back up for more information.

BACKUP FULL + TUESDAY CHANGES

THURSDAY

BACKUP FULL + TUESDAY CHANGES + WEDNESDAY CHANGES

Differential Backup

BACKUP FULL + TUESDAY CHANGES + WEDNESDAY CHANGES + THURSDAY CHANGES

BACKUP FULL + TUESDAY CHANGES + WEDNESDAY CHANGES + THURSDAY CHANGES + FRIDAY CHANGES

Backs up the data that has been changed since the last FULL BACK UP.

BACKUP FULL

MONDAY

FRIDAY

TUESDAY

WEDNESDAY

Differential backups take increasingly longer to perform as the week goes on but provide a faster restore. A backup scheme using differential backups also starts with a full backup. Each subsequent backup includes all the files added or changed since the last full backup. A differential backup does not reset the archive bit, so a new or changed file will be included as part of a differential backup every time. The full backup will reset the archive attributes for all files. When you restore a system, you will need your full backup plus the last differential backup.

FULL

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Last Differential

Correct! Great Job!

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An incremental backup requires less time to complete daily and includes the files and folders changed since the last backup. An organization may choose a combination of full and incremental backups. For example, every Friday the organization performs a full backup. On Monday thru Thursday, an incremental backup includes only the new files and files that changed during that day. An incremental backup resets the archive bit. To restore the entire system, you will need the last full backup plus each incremental backup since that full backup.

Incremental Backup

Drag and drop the backups required for a restore process needed on Wednesday morning.

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Full Backup

Click each type of backup to compare backup strategies.

All Changes Since Backup #1

Differential Backup

Backup #1

Starts with Full Backup

Incremental Backup

Backup #2

Changes Since Backup #1

All Data

Backup #3

Backup #4

Just Changes Since Backup #2

The full backup will require the most time and storage while an incremental backup requires the least amount of time with less archive storage. The differential backup provides a faster restore since you only need the last full backup and the last differential backup.

Compare Back Up Types

Just Changes Since Backup #3

New/ Modified Files

DIFFERENTIAL

Data Backed Up

Click each type of backup for more information.

Lowest

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All Data Since Last Full

Backup Time

Amount of Data Backup

Fast

Slowest

Moderate

Restore Time

Storage Space

INCREMENTAL

Backup Type

High

FULL

Tape Library

Sources of backups

Data Repository

An archive management server aggregates central backup systems. Archive management systems help manage the complexity of multi-tiered backup systems. They time stamp, label and schedule system backups. Archive management systems are also used to restore and test data backups.

Click on each data repository option to learn the role it plays in the backup management system.

Clients/Workstations

Onsite Retention Library – For mass storage of large amounts of electronic data, onsite retention library systems can compress and off-load records that are rarely needed. If an archived record is requested, the system can search for and retrieve the records. This type of application works well for government agencies such as the IRS, Social Security Administration or Veteran’s Affairs because those agencies store massive amounts of data.

Offsite Mass Storate

Onsite Retention Library

Primary Storage Systems – Large organizations invest in high-capacity, high-speed storage systems. These systems provide fast backups and restorations of data. They are used to provide daily backups and backups of live data as it is saved to the local devices. Companies also use these repositories to store all controlled and sensitive data rather than enabling users to save this data on their local devices.

Servers/VMs

Off-site Backup Media Storage

Off-site Mass Storage – Off-site or cloud-based mass storage facilities are used to eliminate single-point-of-failure data loss. Data can be shared between multiple physical locations to eliminate threats form natural disasters, floods or fires.

Archive Management Server

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Off-site Backup Storage – Organizations can also use off-site Backup Media Storage systems. Archive drives, tapes and optical devices can be stored off-site to provide protection from natural disasters, floods or fires.

A tape library is a collection of magnetic tape cartridges and tape drives. The tape library contains tape drives for reading and writing data, access ports for entering and removing tapes, bar codes to track the tapes, and a device that mounts and dismounts the tapes. An organization must figure out how big the library archival set will be. Some large organizations use a tape library as a secondary backup.

Primary Storage

TUESDAY Differential

THURSDAY Differential

SUNDAY Full Backup

FRIDAY Incremental

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TUESDAY Incremental

WEDNESDAY Differential

THURSDAY Incremental

MONDAY Differential

The system crashes on Thursday afternoon. Drag and drop the correct backups that have the shorter restore time.

FRIDAY Differential

WEDNESDAY Incremental

Back Up Challenge

MONDAY Incremental

Incremental

WEEKLY

MONTHLY

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A backup rotation scheme determines how long the backup is retained on the media. Grandfather-father-son uses a minimum of three sets of backups and is based on a four-week cycle. Let’s say that at the end of each day, Monday through Thursday, you run a daily backup. At the end of the day Friday, you perform a weekly full backup, and on Friday of the fourth week, you perform a monthly backup. You would need one set of tapes or optical drives for the daily backups (son), one set for the weeklies (father), and one set for the thirteen monthly backups (grandfather). If the goal is to perform fast daily backups and reduce the overall storage needs, a combination of FULL and INCREMENTAL backups would be used.

Grandfather-Father-Son Backup Retention

Differential

Monthly Backup Schedule Using Differential

If the goal is to provide fast restores and overall storage needs are not a concern, a combination of FULL and DIFFERENTIAL backups would be used.

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The system crashes on Thursday afternoon. Drag and drop the correct backups that had the shorter backup time.

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The system crashes on Wednesday afternoon. Drag and drop the correct backups that have the shorter restore time.

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The system crashes on Friday afternoon. Drag and drop the correct backups that had the shorter backup time.

File Systems

An image-level backup includes the entire operating system, application programs, and all the data associated with them. The backup is saved in a single file called an image. Advantages:  Management is easy since there is only one file that contains the entire backup Save numerous backups on the same disk if the disk is big enough Compress the backup file to save space Deliver hard drive images over the network to one or many systems simultaneouslyDisadvantages:  Requires the backup software that created the image to carry out the restore process

Click Here to Partition and Format Disk

Image Level Backups

ImageFile

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Operating  System