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Questions and Answers about Backups
Q. What is a backup?
When you perform a backup on a computer you are copying everything on the hard disk onto (usually) a tape. These tapes, which look a bit like cassette tapes, can hold a tremendous amount of data and so everything stored on the computer can be copied.
Q. Why would I want to do this?
If your computer has problems and all the data on it is lost, then you can use the backup tape to restore the data to the way it was before the problem occurred. It also makes it much easier to restore the data if you have proper backups, so the costs involved in restoration will be much less.
Q. If I lost all the data currently stored on my network, would I be happy?
This is the question to ask yourself. If the answer is 'not very pleased' (or something a bit stronger) then that tells you that you need to backup your data.
Q. What if I don't bother with, or don't have time for, all this backup nonsense?
You run the risk of losing all the data stored on your computers – pupils' work, pupil records, any letters, administration data, finance data, attendance data, etc. Basically, anything that you currently save on the computer could be lost forever! Even if it were possible to restore some or all of the data, the costs involved could be substantial.
Q. How often should I backup?
Ideally you should backup every day, as then you can always be sure to lose no more than one days work should anything go wrong.
Q. Do I have to backup every computer?
If your computers are on a network and use the main server to save the work you do, you only need to backup the server – the server has a backup device to allow this.
However, if you save your work on other computers, such as an administration computer in the office, then these computers should also be backed up - you may need to buy a new backup device to do this if you haven't already got one on the computer.
Q. How do I backup?
Your technician or support contractor should be able to set up your server (and other computers if necessary) to automatically backup every night. All you then need to do is change the backup tape daily.
Q. How many tapes do I need?
When your NGFL network was put in you were given 10 backup tapes to use in a certain order and on certain days. A backup routine that uses 10 tapes has been suggested by the advisory service and can be found in their publication 'Network Training Manual (Sheffield NGFL Networks)', mentioned in the previous answer. You were also supplied with a cleaning tape that should be used regularly.
Q. Why can't I just use one tape?
If you only use one tape and there is a problem with the tape or a problem with the computer that takes a few days to show up, then you will not be able to restore a good copy from the tape. By having many tapes used in sequence, if there is a problem with a tape you still have others to restore from. Also if a problem takes three days to show up, for example, you can go back to the backup from four days ago to get a good copy.
Q. Where should I keep my backup tapes?
Ideally the tapes should not be kept anywhere near the server. In the case of fire or flood this would help ensure that the tapes do not get destroyed along with the server. If done correctly, tapes would be kept completely off- site, but this is not always practical.
Q. Do I need to replace these tapes?
Yes. The tapes will be getting regular use and may need replacing every 6-12 months, as they will deteriorate in quality with a subsequent loss of data making them useless. Your technician should make regular checks of the tapes to determine if the tape requires replacing.
Q. How much are replacement tapes?
I have seen them available at the following prices on the internet (12/8/02 prices):
DAT - DDS3 – 12GB - £60 for 10
DAT - DDS4 – 20GB - £100 for 10
Cleaning tape - £3
Q. DAT and DDS3/4– What are they?
DAT is a 4mm media format (width), split into different DDS levels. DDS1 covers both 60m and 90m long media, with capacities of 1.3Gb and 2Gb respectively. Next in the DAT line-up is DDS2, 120m long and backs up 4Gb. DDS3 and DDS4 DAT media are 125m and 150m long with capacities of 12Gb and 20Gb. DAT cartridges are very compact, being about the size of a box of matches, and are a double reel system. That is, as the tape is read it is wound off one reel and onto another, similar to a standard audio cassette, except neater. As can be seen below the DAT cartridge is easy to handle being 73mm x 53mm x10mm. DAT is really now the entry level for serious backup situations, with the drive costs being reasonable, being of the order of a few hundred pounds. The media costs are not major either, as the drives are normally fully backwardly compatible, allowing for the selection of DAT media sizes to suit the amount of data to be backed up, the smaller sizes can be had for a few pounds each.
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