1 Maintain System Integrity Maintain Equipment and Consumables ICAS2017B_ICAU2007B Using Computer Operating system ICAU2231B Caring for Technology Backup & Restore Assignments

2 Backing Up Introduction Data Loss Backing Up Methods Incremental Backup Restoring Data Loss Tracking Backups and Restorations Storing Backups

3 Dumb Joke page …

4 Do you backup your files ? How do you do it ? How often do you do it ?

5 Introduction to Backup Never take the reliability of your computer for granted Always backup your data On large systems, backup policy is a vital part of running the system

6 Data loss (causes) Human error –Accidental deletion of files Corrupted Files –Human error –Removing a usb before the file is saved –A software error –Hardware errors –Head Crash Read/write heads damage the surface of the disk

7 Data Loss (causes) A system crash –Power fluctuations –Blackouts –Blown fuses –Cooling failure Software Viruses

8 Reasons for Backing Up You and your organisation’s reliance on your PC to give you timely access to up-to-date information Legal obligations to maintain certain records which might be found on your computer The strong possibility of deleting or modifying files which may need to be restored later Doing a backup of a hard disk that is full before the removing any unneeded data Performing a backup before taking your computer in for service

9 Backup Schedule These questions have to be considered –How often should backups be done (daily weekly monthly)? –When should backups be done (during the day or at night)? –How long should backups copies be kept and how many old backups should be retained? –Where should backup copies be stored?

10 Scenario Consider a small business using a personal computer. The PC has a single hard disk which is used to store all accounts, day-to-day trading details, product details, invoice details, lists of suppliers and customers, and so on. In short, the business depends on the information stored on the hard disk.

11 Backup types A B C

12 Backup Methods A Full Backup backs up everything up each time it is run (see A) An Incremental Backup backs up only new or changed items from the previous Incremental Backup, an must have a Full Backup as the starting point. (see B) A Differential Backup backs up all new or changed items from the last time a Full Backup was run (see C).

13 Pro’s and Con’s A Full Backup takes a long time to run, and a considerable amount of backup media to accomplish. However, a restore from a Full Backup is much quicker. An Incremental Backup takes the shortest amount of time, and the least amount of backup media to accomplish. However, the effort to restore from an Incremental Backup can be very time consuming. A Differential Backup lies between the two in terms of backup time, media size, and restore efforts

14 Backup Storage Media The media type can range from another fixed disk drive, tapes, removable media (such as zip disks, disk cartridges, and flash drives), and DVD/CD’s. The main factors to consider are the size of the media, the speed of the media, the reliability of the media, and the media cost

15 Selected directory Backup Most operating systems come with a backup, and file compression utilities

16 Backing Up: Day or Night? Backups are usually done at night Most files are accessed during the day Backup Utilities cannot run whilst a file is being accessed

17 One role of a Computer Administrator Make sure that there are regular backup procedures put in place This might mean that they perform Nightly and Weekly backups, using scheduler program so they don’t have to stay around till it completes

18 House Keeping in the Office Each computer user may be assigned their own backup media to do their own backups It is important that office staff follow the procedures for an incremental backup Some offices will keep monthly network backups These may go back a full year

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20 Restoring Lost Data Once backed up data may need to be restored This may be due to errors on disk The computer administrator is responsible for restoring lost files The procedures should be written down so others may perform the task

21 Tracking backups and restorations A backup log is necessary because: –You know which set of tapes or disks has the files to be restored –To monitor which areas most often need restoration and should be most carefully backed up –To make sure the backup schedule is sufficient for your company’s needs

22 Backup Log Date of Backup Directories Backed Up Type of Backup 16 th June 2008 C:\winword\files C:\excel\data Full – Weekly – DVD 17 th June 2008 Ditto Differential – daily – DVD 18 th June 2008 Ditto Differential – daily - DVD

23 Restoration Log Date of Restorat ion Directory or Files Needed Backup disks used Reasons For Restore 26 th June 2008 C:\winword\file s\book3.doc 16 th June 2008 Needed old version 4 th July 2008 C:\excel\data\ monash.xls None – not backed up… Wanted a copy to do another tender

24 Storing Backups Storing them nearby is good because they can be accessed There is a risk that they can be destroyed The hardware can be replaced but the data can’t Backups are usually stored offsite Large companies may have many storage locations –Each 5 – 10 km’s from the computing department

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