Article Number: 000151637


A Basic explanation of Backup types and methods as apply to Linux and Windows Dell PC's

Summary: This article explains the terms, conventions and practices behind backups.

Article Content


Symptoms

This article provides information about what types of backup are possible. What are the questions you need to ask before choosing a plan for your Linux or Windows-based Dell PC.


Table of Contents:

  1. What does Backing Up actually involve and why is it needed?
  2. Types of Backup
  3. Backup Methods
  4. File Systems
  5. Recovery

 

What does Backing up actually involve and why is it needed?

 

Backup and recovery are essential on any system. Not having a verified backup and recovery procedure, puts your data at risk of loss.

People often learn this only after their data is lost for good. Any Attempts at recovering lost data loss can take up both a lot of your time and your money. Ensure you have a system in place that protects your data in order to make sure this never happens to you.

There are several questions to ask yourself before you look at putting a plan in place:

  • Why are you protecting yourself against disaster? Does it matter if you lose data? What losses will you suffer?
  • What are you going to backup? The whole hard drive or some of the data?
  • When is the best time to backup your system? How often will you perform a backup? When will you use full backups and incremental backups?
  • Where will the backups be stored? On-site? Off-Site? Cloud?
  • Media type? - Attached storage - USB stick, USB hard drive, tape drive. Backup server?
 


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Resolution

 

Types of Backup

 

There are many different ways and different software out there to provide backup and recovery. Making the best choice for you will have to take several things into account:

Recovery time objective

(RTO): How fast would you need the data back up? Can you keep working if the data is not recovered for a day, a week, and so forth?

Recovery point objective

(RPO): How much data are you prepared to lose? Can you lose two hours, two days or two weeks of data?

Example: if you can withstand losing one week of data then a weekly backup would be sufficient. However, if you can only withstand losing one day then you would need to employ a nightly backup - or a variation.

This document will cover three basic types of backup:

Full

A full backup backs up everything in the location you select.

Incremental

An incremental backup backs up everything that has changed since the last backup.

Differential

A differential backup is the same as an incremental if your running Linux or MacOS. In Windows it is a backup that does not clear the archive bit.

SLN265961_en_US__1icon Note: Sometimes in Windows systems you may use a combination of these three types to accomplish the type of backup you require.


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Backup Methods

 

Depending on the money, you have to spend and the specific RTO and RPO you have selected you can choose from these three methods:

Manual

Manual backup would be initiated on a schedule by you and is the most common method for home users to backup your files. This method is also the least reliable, but is the cheapest.

Local automated

Automated backups are ones that target media physically attached to the PC being backed up. Advanced home users and small businesses will often use this method.

Remote automated

Automated backups are ones that target media over a network. This type of backup is used by businesses that have money they can dedicate to the process of backup. As the organization becomes more mature, they may even stage the backup on multiple mediums and increase the distance between backup and production systems.

 
SLN265961_en_US__1icon Note: With the surge in small online storage accounts, you may find that your needs are met by a combination of these three methods.
 


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File Systems

 

Ubuntu file systems record three different times for each file:

mtime

Modification time is when the value is changed when the contents of the file is changed.

atime

Access time is when the value is changed when the file is accessed. The atime can change when a backup utility or script reads the file as well as when a user reads the file.

ctime

Change time is when the value is updated whenever the attributes of the file change. This can be ownership or permissions.

 
SLN265961_en_US__1icon Note: File system backups change atime while raw device backups will not. If you are implementing incremental or differential backups, this is important.
 

Windows file systems record only 2 for each file. It is either set or clear.

Archive

 

When set, it indicates that the file has changed since the last backup operation. Windows file system sets this attribute on any file that has changed. Backup software then has the duty of clearing it upon a successful backup.

 

 
SLN265961_en_US__1icon Note: Many people consider only the backup part of this process and do nothing to verify that the backup can be restored. It is important to test that your back-up process is working and that data can be recovered.
 


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Recovery

 

It is crucial that your backups be tested by restoring from them.

Here are some tests that you should do to ensure you can recover from a loss:

  1. Restore many single files

  2. Restore an older version of a file

  3. Restore an entire folder

  4. Restore an entire drive and compare the checksum

If you do not test, you may find out that nothing was being backed up when you need to restore the files in reality.


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Additional Information:

 

SLN265961_en_US__1icon Note:
Software support is by Canonical through the following methods:
Technical Support is provided by Dell:


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Article Properties


Affected Product

Desktops & All-in-Ones, Laptops

Last Published Date

21 Feb 2021

Version

3

Article Type

Solution

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