How often is enough?
A common question is: how often you should back up? The short answer is you probably should carry out some sort of backup at the end of every workday, be it incremental or a full backup.
There are very few businesses that can afford to lose more than a day's worth of data. The next obvious question is when should you carry out a full backup and when an incremental?
And again there is a short answer that in itself involves a question. How much time can you afford to be down if you have a catastrophic data failure in your primary storage?
With a full backup you simply remedy your primary storage problem by running the most recent full backup tape. It can of course become quite expensive, not to mention time consuming, to carry out a full backup every night.
Some businesses run incremental backups every weeknight and then a full backup over the weekend. This saves money as the incremental backups through the week may fit on a single tape, or several much smaller tapes, and it saves time as the time-consuming full backup takes place over the weekend when hopefully your system is not as busy.
The downside of this system is that restoring your data will take longer in the case of a large-scale storage failure. You will need to restore the last full backup, followed by several incremental backups to get the system up to date again.
Oh, and just a bit of common sense--your precious backups are not much use if the server room burns down and that's where you store the tapes. It makes sense to store your backup tapes at a different site, and we don't mean in an adjacent room. That way, if your hardware does go up in smoke, or is stolen for example, it is simply a matter of buying new hardware and restoring your data.
