Backing up. It makes your files safe and fills your tummy with a warm safe feeling, like jam sandwiches, or primary school summer holidays. So why do people still loose important files. What can possibly go wrong?
In theory backups make your data safe, but what constitutes a good backup. In essence a backup is straightforward, it's a duplication of your data, so that should one source fail, everything you need is available in another place. In practise it's a hideously complex mess of strategies, media formats, compromises and at some point data loss. So what's the best way forward?
The best starting place is have some sort, any sort of backup. With a Mac the simplest starting point is Time Machine. An automatic copy of your data to an external drive connected to your Mac, or to a remote Time Capsule if you are feeling wealthy. The ease of use and automated nature of Time Machine makes it ideal to actually get back ups done. You will need to be running OS X 10.5 or 10.6 to use time capsule but the numbers of people still using 10.4 (and lower) is rapidly falling, and we'll deal with you later on in this article.
Time capsule backs all your data up by default and makes copies of any new files as you go which you can easily retrieve should you accidentally delete a file. This ease of recovery however leads to one of the commonest errors when using Time Machine as backup. Lulled into a false sense of security, it's easy to misuse Time Machine. With files stored on the backup drive, many users happily delete data from their main drive. After all it's "backed up" isn't it? Not as soon as you delete the original it isn't. Once this happens your data suddenly exists in only one place, your Time Machine drive. Should the drive fail, the backup file become corrupted or your Time Capsule fail (this one is particularly common) your data is, well, history. Rule one is, never rely on your Time Machine drive alone, it will fail you. This way of using Time Machine is due to the confusion between backing up and archiving. If you no longer require a file you have two options, delete it (bye bye) or archive it. Archiving means moving it to long term storage. This way the data continues to exist in two places, on the Time Machine drive and in your archive. Of course eventually your TM drive will fail, the drive will fill up, or you will move on in some other way, leaving your archive as the sole copy of your data. This is why archives are usually duplicated, either by making two copies of any DVD you create or more usefully on two different types of storage media, ie DVD and hard drive.
Of course Time Machine isn't the be-all and end-all of Mac backup, there are other ways to achieve the same effect. You could always use the startlingly effective free application Super Duper (or Carbon Copy Cloner) to make a simple copy of your working hard drive at a set time every day. This way should the worst happen you can recover your work back up to the previous day. You won't get multiple copies and a historical record of your files but it's simple to use and understand and generally avoids the deleted files problem that plagues Time Machine users. Of course if you are running 10.4 or earlier, then your backup strategy may start here. Other solutions that may work for you are simple apps like LaCie's SilverKeeper. This offers automated backup at set times as well as the option to keep older backups until the storage media is full (normally this is set to keep a weeks worth of backups).
Backup fanatics will also consider off site backup. The choices are many, Mozy, Mobile Me (yeah right), Carbonite, etc, they all work the same way, by copying data over the internet to a remote storage location. Great if your entire house burns down, cheap, but limited by your broadband connection speed to how long it takes to transfer large data sets up into the cloud. Cloud backup helps you fulfil another maxim for successful backup known as 3,2,1. 3 copies of each file (the original and 2 backups), 2 types of media and 1 offsite or online. While 3,2,1 may prove impractical in day to day use, the basic idea of 3 copies and physical separation between them is a good one.
The take away from this is simple, make sure your backup is actually a backup and understand the difference between backing up and archiving. Both involve maintaining your data in at least two places at the same time, but one is an active strategy while one is dedicated to long term storage.
There is one last element involved in backing up. Testing. Remember the warm tummy feeling? Well imagine how that can turn to set concrete if you should discover that your backup is not working. Once your backup is up and running, give it a test. Make sure that your files are where you think they are, check that your data is making it onto that external drive, test out your Time Machine restore.
Once you have a working backup, understand how it works and why, and a cupboard (or two ) full of archived data and have checked and tested everything, then you can properly enjoy your warm feelings. All together, aaaaahh, summer.
