Network Software

MODULE 2:  MAINTAINING NETWORK SOFTWARE

UNIT 2: PERFORMING PERIODIC BACKUP

At the end of this unit trainees should be able to;

v  Define Backup

v  Explain Reasons for Performing Backup

v  Describe Types of Backup

v  List Backup software and its characteristics

v  Perform backup

Introduction

One of the cardinal rules of using computers is back up your file regularly. Most operating systems contain utilities or commands for performing backup.

What is Back up?

Is the process of copying files to a second storage medium as a precaution in case the first storage medium fail.

The following are Reasons for Doing Back up

v  Hardware Failure

v  Software Failure

v  File System Corruption

v  Accidental Deletion

v  Virus Infection

v  Theft

v  Natural Disaster

Types of Back up:

1.      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 or differential 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.

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.

2.      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.

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.

3.      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 than incremental 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 than with Incremental backups

Advantages

• Much faster backups than Full backup
• More efficient use of storage space than 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 than full backups but simpler than incremental backups. Only the full backup set and the last differential backup are needed to perform a restore.

Full PC 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”

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.

4.      Local Backups

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.

5.      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.

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.

6.      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

The following are features that you may want to consider carefully when looking at PC Backup Software

v  Wide Device Support

v  Operating System Support

v  Backup Type Selection

v  Scheduling and Automatic Operation

v  Backup Verification

v  Compression

v  Security

BACKUP MEDIA

Backup media these are storage devices where backed up data are stored

 These are

        i.            Magnetic tape

      ii.            Hard disk

    iii.            Optical disk

     iv.            RAID

       v.            Remote backup service

v  HARD DISK

A hard disk in another location can be used for backup.

A laptop can be transferred and backed up to the user’s desktop computer hard disk.

These media have large capacities and can be stored away from the main computer.

v  RAID systems

instant backups in real time normally found in server computers

v  MAGNETIC TAPE

Removable media with large capacity – mostly for business use, using specialist drives in servers. The tapes can be removed and stored away from the server, giving a backup in another location.

v  Remote backup service

Remote backup services can be used for online backups

Note:

Back up media like

 

ü  CDR or DVDR Disk     

                                   

ü  Removable flash drive              

 

ü  Removable hard disk

These media are suitable for backing up home computers or for small business use

Summary

•         Data must be backed up in case it is corrupted, lost or stolen.

•         Media used for backup needs to be selected according to the data being backed up.

•         Data can also be backed up remotely, using online services.

BACKUP APPLICATION AND DATA FILE

You can use Windows Server Backup to create backups to recover applications and data. To do this, the application must contain a Volume Shadow Copy Service (VSS) writer so that it can register with Windows Server Backup, and the application and VSS writer must be running at the time the backup is created..
Then, to back up a supported application, you will need to first:

• Identify a location for storing your backups—backups of applications must be stored on attached disks or remote shared folders, not on optical or removable media. Make sure that any hard disks for storing your backups are attached online. As a best practice, if you are using an external hard disk, make sure that it supports either USB 2.0 or IEEE 1394. The disk should have at least 2.5 times the storage capacity of the set of items that you want to back up. If you a dedicated disk for storing backups, it should either be empty or contain data that you do not need to keep because Windows Server Backup will format this disk as part of preparing it for the backup. If you store your scheduled backups in a remote shared folder, the backup will be overwritten each time you create a new backup. Do not choose this option if you want to store multiple backups.
• Decide what volumes to include in the backup—to be able to recover an application from a backup, you must have backed up the full volume or volumes that contain the application. If creating a scheduled backup, decide whether  to run backups once a day or more often.
• After the backups start running, monitor the status using the Messages , Status , and Scheduled Backup sections of the snap-in default page.

Procedures  to create a scheduled backup to use to recover applications

1.      Click Start , click Administrative Tools , and then click Windows Server Backup .

2.      In the Actions pane of the snap-in default page, under Windows Server Backup , click Backup Schedule . This opens the Backup Schedule Wizard.

3.      On the Getting Started page, click Next .

4.      On the Select Backup Configuration page, do one of the following, and then click Next :

• Click Full server (recommended) to back up all volumes on the server, including the volume or volumes that contain the application. This is the recommended option.
• Click Custom to back up just certain volumes, and then click Next .
1. On the Select Items for Backup page, click Add Items . In Select Items , select the check boxes for the volumes that contain the application. Click OK .
2. On the Select Items for Backup page, click Advanced Settings , click the VSS Settings tab, and then select either VSS full Backup or VSS copy Backup . Click OK and then click Next .

5.      On the Specify Backup Time page, do one of the following, and then click Next :

• Click Once a day , and then select the time from the drop-down list to start running the daily backup.
• Click More than once a day . Then, to select a start time, under Available time , click the time that you want the backup to start, and then click Add to move the time under Scheduled time . Repeat for each start time that you want to add.

6.      On the Specify Destination Type page, do one of the following and then click Next :

• Select Back up to a hard disk that is dedicated for backups (recommended) .
1. On the Select Destination Disk page, select the check box for the disk that you attached for this purpose, and then click Next .
2. By default, the likely disk or disks are shown in the list. These disks are external disks that can be used for moving backups offsite for disaster protection. If the list is empty, or the disk that you want to use is not listed, click Show All Available Disks . In Show All Available Disks , select the check box next to the disk that you want to use to store the backups, click OK , and then on Select Destination Disk , select the check box for the disk again. This disk will no longer be visible in Windows Explorer—to prevent data from accidentally being stored on the drive and then overwritten, and to prevent accidental loss of backups.
3. A message informs you that the selected disk will be formatted and any existing data will be deleted. Click Yes . Do not click Yes if you have data on the disk that you need. To use a different disk, click No , and then select a different disk under Available disks .

Important

We recommend that you record and then physically attach the label information to any external disks that you are using to store backups. If you need to recover data from the backup stored on the disk, you will need this information to identify the disk.

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GEDIT