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How to avoid Data Recovery
Posted by Mark on Sep 23, 2008
We often get asked “what could I have done differently” when data has been lost, especially when a recovery could not be made or the cost of the data recovery work was rather high.
The simple answer is often “made sure you had another copy of the data”. A hard disk crashing might result in annoyance, the cost of a replacement disk, the time to re-install the operating system and all of the applications, but this is nothing compared with the time that has been spent working to create spreadsheets and to write letters or other documents. Worse still is when the data is a record of an event that simply cannot be repeated, it is not possible to travel in time and go back over your children’s early years, and holding that wedding again is not usually an option.
The simple answer I gave is alright so far as it goes. Once person with whom I recently had dealings had ensured that all data was backed up to another USB hard disk, but this disk was sitting on top of the disk containing the main copy of the data, so when one was knocked to the floor the other was only a split second behind it.
There is not 100% reliably safe storage method, but the risk can be reduced to the point that it is close. House fires and water leaks are relatively common-place, so don’t keep your backup where it will be damaged by the same event that destroys the original copy. Asteroids hitting the earth bring with them a whole load of problems that will probably render data security a rather secondary consideration, so keeping your backup copy 600 miles away just in case is probably going rather over the top.
Making a backup is not enough, testing a backup is essential. It is, after all, only really a backup if you can restore from it. We’re in the process of recovering data from a pile of CD-R disks that had full backups of a company’s data that had been diligently made over the course of two years, but where the first attempt to restore anything was after the server disk died horribly. There are severe problems with these CD-R disks and there is a strong likelihood that much of the data will never be recovered.
I have long held that the steps that are taken to preserve data should reflect the value that the data has, if it is important then keep several copies, perhaps use different technologies such as tape as well as hard disk and DVD, and make certain that test restores are done. I have never forgotten the tape data recovery I did in 1992 where there was nothing wrong with the tape, there was nothing wrong with the backup, but the software was obsolete and the only copy that existed was backed up on the tape. A rather expensive and unfortunate Catch-22.
