Section 2
For backing up school networks, there are 4 types of backing up systems. These are disk mirroring, RAID systems, magnetic tape and the grandfather-father-son system.
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Disk mirroring is a technique in which data is written to two duplicate disks, at the same time. This is a very good backing up system as if one disk drive fails; the system can switch to the other disk drive without data being lost.
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The second backing up system is the RAID system. This stands for redundant array of independent disks. This is a way of storing the same data in different places on multiple disks. Software that can let the system switch between several other disks usually accompanies this type of system.
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Normal type of backing up is done on a magnetic disk, however at certain times, a magnetic tape is used. Tape is a cheap and convenient medium for back ups and is also used for archiving past transactions or other data that may be needed again. The tapes store between 20Gb and 200Gb, which can be brought for £10-£60.
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By using the grandfather-father-son system, it is possible to recreate a masterfile if it is lost. This scheme uses three sets of tapes for daily, weekly and monthly backup sets. The actual number of tapes required in each media set will vary depending on how much data you need to backup. The first set, "Son," represents your daily backups. A second set, called "Father," is used to perform full backups on the day in which you do not perform a daily backup and the final set of three tapes, called "Grandfather," is used to perform full backups on the last business day of each month and can be reused quarterly. This rotation scheme will back up data on a daily, weekly, monthly, and quarterly basis.
Out of all the types of back-up mediums, I personally feel that the tape drive is the best one to back up a school network. This is because, all the data is backed up on one type, the tapes are rewrite able, meaning that it can be written over again as many times, they are small, convenient and robust. Also, information can be easily stored. Lastly, if one user looses a file, you can search through the tapes, and find that exact file and transfer it back onto his account.
Some key issues need to be addressed when planning a backup strategy. For a backup strategy to take place, there are several factors, which need to be considered when developing a back-up strategy.
Schedule: If the data changes frequently, it will need to be backed up more often. Other data, such as data, which changes less often, may only require backing up once a week. It will also need to specify how long the backed up data should be kept for, as it backed up data can be overwritten.
Location: When the data is backed up, the tape should be kept away from the main system and another copy should be transferred offsite in case of a fire or an explosion.
Responsibility: Someone should be put in charge of making sure the back up is completed. Although the backup strategy is in routine, a general manager should also be kept in charge and when the responsible person is away, another person should be put in charge.
Recovery: If something disrupts the data on the network such as a theft of a virus attack, then it is essential to load the backup tape now and then to make sure that the data can be recovered if it is needed.
Backup medium: The most appropriate medium for backing up a school network is using DAT, and by using the grandfather-father-son backup system. The capacity of the tape, depends on, the volume of data to be backed up, the expense and the convenience of the medium.
Dos and Don’ts
After backing up the data, do not leave the backup tapes lying around, as they can be stolen very easily. Secondly, do not leave the backup disks near the computer, because if the computer is stolen, then there is a very big chance they will take the backup disks with them. Thirdly, do not leave the disks, lying around or by keeping it in drawers.
You should at least have more than one backing up tape, and at least one of them should be left far away from the main system, and preferably in another site. Also, if the back up data is expensive then the school should buy a fireproof and a waterproof safe, where the backups tapes can be safely placed incase of an emergency such as a fire and they wouldn’t need to be transported to another site.