I got hundreds of emails and tweets asking for Glacier support. Turns out it’s a good option for some scenarios (even with the slow restore time and possible extra Amazon charges). People want to use it for big stuff like iPhoto libraries, videos, etc that get too expensive in S3. They use it as a secondary backup, so they don’t expect to actually restore unless their whole house burns down, taking their primary backup with it.
This is exactly how I use online backup, and how you should: as a secondary or tertiary backup in case my primary drives, my Time Machine drive, and my SuperDuper clone all simultaneously fail or are lost. (Such a scenario could be possible if, for instance, a massive power surge blows through my UPS and fries my Mac Pro and everything connected to it while the SuperDuper clone is connected.)
I’ve read great things about Arq and wanted to use it for a long time, but my huge backup set (about 800 GB) made it poorly price-competitive with Backblaze, my current online-backup service of choice. But with support for Amazon’s new, limited, much cheaper Glacier storage, Arq is now in the ballpark.
I’m giving it a try alongside Backblaze now.