Thursday, March 03, 2011

Backing Up Your Digital Images

One advantage of digital over film that is often overlooked is the ease with which you can make backup copies of your image files to protect against loss. I have heard people bemoaning the apparent fragility of computer hard disks, but given that storage is so cheap* these days, you have no excuse for not creating backups!

It is important to consider the other risks, apart from hard disk failure, as well. Loss due to fire or theft is probably a considerable risk to, especially given that our hard disks tend not to stay in use for too long as we upgrade for more capacity or even replace whole machines after a period of years.

The first and most important thing is to consider the risks and then devise a strategy to deal with them. For most people these are:
  1. Loss due to hard drive failure
  2. Loss due to fire or theft
  3. Loss due to accidental deletion
Next, consider how more or less likely these are. For example, most of my work is done and stored on a desktop workstation. If this was a laptop, then I would consider the risk of theft to be higher, especially if I transported that machine from place-to-place frequently.

My strategy to deal with item 1., is that my desktop workstation has 3 disks: one contains the Operating System and programs; the other two contain my image files, in a mirrored RAID configuration. Mirrored simply means that my image files are written to both disks, and should one of these drives fail, the Operating System (Windows 7 64 bit) will warn me. Once the faulty disk is replaced, the files on the 'good' disk will be 'mirrored' again automatically, thus restoring protection for my files.

To cover item 2., fire or theft, I use a pair of external hard disks, on each of which I make a backup of my image files using EMC Retrospect. I alternate the disks and never have both disks in the same location, i.e. one is always stored off site. Retrospect also takes care of item 3., accidental deletion, as it allows you to restore earlier versions of individual files quickly and easily.

I also have a laptop and a netbook which occasionally have image files on when on location, these are backed up onto a rugged portable hard drive, and are copied to the desktop machine as soon as I return to base. To back up the laptop I use Acronis True Image, and I also use this to backup the Operating System disk in my workstation. As it's name suggests, True Image creates an image of the whole disk which can be used to re-instate the machine should the laptop disk fail - the image is simply copied to a replacement disk and the machine is restored complete, as it was.

* Maplin are currently selling 2TB external hard disks for around £85!

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