Petteri’s Pontifications is definitely a site about photography worth a few hours of your life. Recently, Petteri seems to have been busy revamping his digital darkroom, and this includes doing a write-up on Information Security for the Digital Photographer. This inspired me to write a few lines about my own backup solution.
Some background. I have a collection of DV tapes, mostly with the usual shots of my children growing up. Currently, this amounts to roughly 200 GB of data. My DSLR camera produces an astounding amount of data on a constant basis – at this time I think my photo collection clocks in at around 30 GB. Add in a few system files, a bit of software and games, and I have a fair amount of data to back up. To put it another way – DVDs feel like floppy disks did a decade ago.
Harddrives fail. They fail often. In my case, I have lost about three drives a year—two years running. That includes both laptop drives at work and PC drives at home. Right now my Linux firewall is doing its best to keep up that track record. In my eyes, this makes single hard drives bad options for backups.
A key question you must ask yourself is “When disaster strikes, how much am I prepared to lose? A week? A month? A year? Or three year’s work, as a relative of mine did?” The answer to the question determines how often you back up, and how often you off-site a copy of your backups.
Another important question is “How far back do I want to be able to go in history?” Disaster strikes rarely, but errors happen often. You will want to restore individual files one day.
Backups need to protect against errors. The simplest form of backups retain only one copy—the latest one—of each file. The downside to this is that any corrupted files you back up will overwrite a perfectly good copy. Why is this relevant, you ask? Well, hard drives that fail tend to start out by corrupting files. Another important source of such errors is humans. If you overwrite the wrong file and don’t realize it until you overwrite your good copy, again you lose.
I needed a backup solution with the following properties:
- Fast in daily use
- Retains history
- Scales in capacity
- Robust on-line solution
- Many off-line alternatives
I have a NAS unit, currently a 1 TB TeraStation set up in a 750 GB RAID5 configuration. Any NAS disk would do, but RAID is a big plus. Some people prefer Firwire or USB2.0 removable drives, but my history with harddisks is not…encouraging.
I use EMC Retrospect to back up daily. The daily backup runs in 10-20 minutes, and covers all changed files on my workstation. The backup includes full verification of all copied files. Retrospect retains copies for each day of the last week, each week of the last month, and as many months as fits on the backup drive. I tried other, “cheaper” solutions first. My advice is: get a good solution right away. For instance, Acronis had the habit of first destroying the old full backups before starting a new one. If I interrupted a full backup, I effectively lost that backup set. Not reassuring.
When I download photos from my CF cards, copies are automatically made to the NAS unit. These copies are retained in addition to the actual backups.
My off-site solution is still in flux. Currently I use Retrospect to backup my photo collection to DVDs. Whenever a DVD fills up, about once a month, I can carry it to off-site storage. The DV stuff is too much data for this, so I just off-site the original DV tapes and hope they don’t rot [they will]. I am considering a removable disk as an alternative.