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ESSENTIAL BACKUPS

The aim of creating a backup is to make sure that a computer system can be returned to its original state if data has been lost or corrupted. Creating a strategy and religiously sticking to it is vital. ESSENTIAL BACKUPS. ESSENTIAL BACKUPS. Factors that should be considered when backing up:

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ESSENTIAL BACKUPS

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  1. The aim of creating a backup is to make sure that a computer system can be returned to its original state if data has been lost or corrupted. Creating a strategy and religiously sticking to it is vital. ESSENTIAL BACKUPS

  2. ESSENTIAL BACKUPS Factors that should be considered when backing up: Storage medium depends on the quantity of data. Frequency of backup depends on how often data is updated or added No. of backup copies kept also depends how often data changes. Weekly will produce more copies than monthly. What will be copied: full (all data); differential (just changes since last full backup); or incremental (changes since last incremental….probably daily).

  3. ESSENTIAL BACKUPS Factors that should be considered when backing up: Recovery procedures: how quickly recovery data is needed. Incremental takes much longer to restore. Location of backup – where are you keeping the data? The more sensitive the data is, the more security you will need to provide. Off site locations make more sense than storing it in the same building. What would happen if there were a building fire?

  4. ESSENTIAL BACKUPS A backup strategy needs a well documented and tested recovery procedure to ensure the backup data is restored properly A well documented plan should provide roles and responsibilities to all staff regarding procedures. Alternative hardware if the originals have been destroyed must be considered. Original software such as operating system and application programs to run the data must be available.

  5. ESSENTIAL BACKUPS Different types of systems may require different types of backups. Small systems or limited data may use online backup options. Disk mirroring: storing identical data on 2 different disks at virtually the same time (RAID). Disks can be in different locations.

  6. ESSENTIAL BACKUPS DAT is magnetic tape and holds 12-20GB with transfer speeds up to 150Mb per minute. This is good for small companies who may not mind being without data for several hours while the data is being restored. Disk mirroring is fast and the backup is always up-to-date, but the equipment can be very expensive.

  7. ESSENTIAL BACKUPS Backup files must be kept in a separate location to the original file in case of fire or theft. Sometimes a fireproof safe is used to store backups in the same building. Some backups are kept at another building owned by the company. Remote backups can be transmitted over a WAN to the firm.

  8. ESSENTIAL BACKUPS Backup files must be kept in a separate location to the original file in case of fire or theft. In large cities there are firms that provide a backup service. They come and collect the backups daily and store at their own premises. If disaster strikes they will return the backups immediately.

  9. ESSENTIAL BACKUPS Anytime data is vulnerable, one should consider compressing and encrypting the data.

  10. ESSENTIAL BACKUPS Types of Backups Full Backup – A copy of the complete system is copied each night. A different tape/disk is used each day. Restoration is easy as the system can be restored from just one tape/disk. However if the volume of data is large then the backup may take hours and might not be completed before the next days business begins.

  11. ESSENTIAL BACKUPS Types of Backups Differential Backup – One full copy of the system is copied to tape/disk. This is often over the weekend. Only the changes to the data are copied to the tape/disk during the week. This allows the data to be restored with a maximum of just 2 tapes. It takes longer to restore the original data as all changes must also be applied to the full weekend backup. However, the data is possibly much more current than the weekly full backup alone.

  12. ESSENTIAL BACKUPS Types of Backups Incremental Backup - One full copy of the system is copied to tape/disk. Only changes to that days data are copied to the tape/disk during the week. This allows the data to be restored with a maximum of 6 tapes. It takes much longer to restore the entire data as each daily tape must be applied to the full weekend backup. Data can be recovered from a single day fast. (The overall backup is faster as the changes are only copied once.)

  13. ESSENTIAL BACKUPS As tapes are stilled used, the quality and limited amount of use of a tape is an issue. The Grandfather, Father, Son Method: If data is updated on a daily basis then tapes are labelled by the day of the week. A different tape for each Friday in the month and a different tape for each month of the year. Mon, Tue, Wed Thur tapes are overwritten weekly but Fri tapes are overwritten monthly. You will need 4-5 Fri tapes. This means there are over 20 generations of current backup tapes in this system.

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