Note: My recommendation to use a USB thumb drive is out of date. It turned out to be too slow. If you have a large library I now recommend using a $100-200 SSD.
As a traveling photographer I need to keep all of my photos backed up. Right now I have over 70 gigabytes of raw photos from my Leica M9 and soon they’ll be too big to even fit on my computer’s 256 gigabyte drive.
I also like to have a mirror of my full disk, so I’ve settled on a multi-tiered solution: a permant backup of my raw files to Amazon S3, a local mirror to an external drive using SuperDuper, and external full drive mirroring to Back Blaze.
If you want to store lots of data I recommend the Seagate Backup Plus Slim. It’s an insanely small drive, reasonably fast, and good for Time Machine or SuperDuper backups. I had one until I dropped it and it stopped working. Thankfully you can buy drive insurance from Amazon, but I haven’t had enough time in the United States to try to get a replacement.
My new solution is to use a 256 gigabyte flash drive to mirror my system. It’s a lot slower than an external spinning disk or SSD and my first backup took 11 hours, but subsequent backups only take 30 minutes. The benfit is that a flash drive is even smaller than the Seagate and for 256 gigabytes it was only $100.
I keep a full mirror of my MacBook running to BackBlaze in the background at all times. It’s not perfect because my bandwith is rarely fast enough to push up the gigabyte of new photos I take every day. Right now I’m 15 gigabytes behind.
One downside of backblaze is that it only keeps a backup of what’s been on your drive in recent memory. I will eventualy want more than 256 gigabytes of raw files backed up, so I also push them to S3 before cleaning up space on my local disk.
I use Transmit to backup to S3 and set it to delete old files. Storing a gigabyte of data on Amazon only costs about 3 cents per gigabyte per month, so storing 70 gigabytes costs me about $2.10 each month. That’s a good price for the security of knowing my photos are safe forever.