Sys Admin: Backup

Please heed this warning:

If data on your hard disk is lost due to a malfunction, it will probably be the case that it cannot be recovered unless it has been backed up to removable media (floppy disks or tapes). When the data is recovered from the media, it will only be as up to date as the last backup.

THEREFORE BACK UP OFTEN. IF YOU IGNORE THIS WARNING YOU WILL REGRET IT AND WE ASSUME NO RESPONSIBILITY.

Tapes and removable media are not infallible either. Keep at least three generations of back up on the go, backing up on to the oldest copy each time. Treat media with respect, in accordance with the warnings given.

Ask for guidance from your hardware maintenance company if a back up program gives a warning message - it usually means the back up was unsuccessful. You may have a hardware problem. DO NOT BACK UP IN SUCH CASES ON TO TAPES WHICH DID BACK UP SUCCESSFULLY - YOU MAY BE DESTROYING EVEN THE OUT OF DATE COPIES OF YOUR DATA. WHAT WOULD YOU DO THEN?

In the event of the operating system having to be reinstalled on to a new hard disk, or your data reinstalled. For this purpose ourselves or the hardware company will need a valid backup.

Please make sure, if you are system manager, that you know how to check your backups, and ensure that backup's are being done correctly.

Remember to label your media in the order they are used and you should use at least 3 sets of disks/tapes, using them in rotation. Backups should be done regularly (depending on how much you want to type in again). Again this is your responsibility and no-one else's.

Why backup?

• Human Error: 95% of data loss is caused by users accidentally deleting files
• Hardware failures: Despite the high reliability of today's systems, failures still occur.
• Natural disasters: Fire, flood and earthquake can cause catastrophic failure
• Malicious acts: Files may be lost or corrupted by viruses or even sabotage. Computer theft is increasingly common.

How to backup

• The WHOLE system
• Just the data files

There is a utility shipped with PremVet 5 called 'tapeback' that will copy onto tape just the PremVet data files. This is intended as a quick security copy - it is not designed for end of Day/Month backups.

For full piece of mind we strongly recommend using a third party backup utility such as Backup Edge. These programs are very robust, will validate the tape has been written correctly and provide user friendly tools to restore the system in the event of a crash.

The 3rd party backup programs (Supertar's) will backup the whole hard disk and not just data files. This means there is a much reduced downtime should the disk need replaced, or is the case of O.S. upgrades the ability to have a complete valided image prior to the upgrade is paramount.

If you elect not to use one of the SuperTar's make sure you are doing a full backup and that the data is indeed being backed up. There is a guide in the FAQ section for those of you wanting to 'roll your own' backup schemes.

Notes on tapeback

tabeback will check, when started, that no-one is currently logged into the vet system, if they are, then it will abort. You can alter this behaviour by adding the -v option which, will by-pass the check.

/etc/default/tapeback

Tapeback looks in the above file for a list of files to backup. This file will be created the first time tapeback is used and will contain as a minimum:

	/etc/default 
	/usr/relnotes 
	/usr/local 
	/usr/utilities
	/u

These are the files essential to the working to Premvet 5. If you have any other applications, you can include their location here and these will be automatically backed up.

Note: We strongly recommend you invest in one of the 'Super Tar' products. These are much improved versions of the backup software that comes with Unix/Unix and make backing up and restoring VERY easy. A full restore with one of these will take 10 mins + tape restore time compared with 4+ hours.