11.1.2.3 describe data protection measures such as data backup and disk mirroring 

12.1.2.2 use data protection measures such as data backup and disk mirroring

Data backup

One of the ways to protect your data is to back up your data.

A backup is the creation of a copy of data or files for storage on another disk or on another server.

Important files should be backed up periodically as files and data can be damaged, accidentally overwritten, or deleted.

A schedule is defined for the backup. Usually, the company has a person who is responsible for backups, as this process must be controlled.

Keep your backups in a secure location. It can be a removable disk or cloud storage.

The backup media or files must be tagged to know when the backup was created and what it contains.

*Look at the video*

Video: by PowerCert Animated Videos 

Date of link: 29/11/2020 

Advantages and diadvantages of using data backup

Advantages

• We can recover data if the original data will be lost
• You can store multiple copies in different locations

Disadvantages

• You will need extra memory to store a copy
• If your backup will be in the same room as the opiginal, then in case of fires, floods, this will not save your data

Two types of backup

• Local Backup

For this type of backup, portable storage is used (removable hard disk, flash memory, CD disks). It's easy to carry with you and your files will always be available to you.

• Remote Backup

This is also often referred to as cloud backup, which is when the copy is held in cloud storage.
This type of data backup is safer than home storage. It will not be affected by floods, fires and other things that can happen where you live. Whatever happens, your files will be safe.

How can I back up my files?
If you want to back up important files, use an archiving program.

• Put all your files in one archive
• Place a copy on a removable hard drive, flash memory, CD-ROM, or cloud storage.

Some programs have a data backup function. In this case, it is enough to configure the backup settings.

*Look at the video*

Video: by Eye on Tech 

Date of link: 29/11/2020 

Disk mirroring (also known as RAID 1)

Disk mirroring is the replication of data across two or more disks. 

When mirroring, all involved disks are exact copies of each other. The default data synchronization is performed.

A disk mirroring strategy used to protect a computer system from loss of data and other potential losses due to disk failures.

The best use of this strategy in systems where the high importance of data storage, such as a standard application servers or systems that require high reliability and performance.

*Look at the video from start to 2:26*

Video: by PowerCert Animated Videos 

Date of link: 29/11/2020 

Advantages and diadvantages of using disk mirroring

Advantages 

• This technology is simple and easy to implement.
• Provides high fault tolerance when working with two disks.
• If one hard drive fails, the data can be retrieved from the other mirrored hard drives.

Disadvantages

• The usable storage capacity is only half of the total disk capacity.
• You cannot replace a failed drive while the computer is running.
• If a virus attaches to a file and starts replicating, this will also happen on the mirrored disk.
• If you accidentally delete a file on one disk, it will be deleted on the other.

Questions:

1. Explain terms "backup" and "mirroring".
2. Explain why "backup" and "disk mirroring" are data protection methods

Exercises:

Ex. 1

Ex. 2

Exam questions: