Backblaze, Arq, and External Drives
Backblaze works best if you leave the external hard drive attached to your computer all the time. However, Backblaze will backup external USB and Firewire hard drives that are detached and re-attached as long as you remember to re-attach the hard drive at least once every 30 days. If the drive is detached for more than 30 days, Backblaze interprets this as data that has been permanently deleted and securely deletes the copy from the Backblaze datacenter. The 30 day countdown is only for drives that have been unplugged. There is no countdown for local files.
If you are going on vacation for a long time, you can shut down your computer with the external drive attached. Backblaze does not detect that the external drive has been unplugged and won’t start the 30-day countdown. You can then leave your computer off and unplug your external drive for six months, and Backblaze will still keep all your files backed up including those on your external drive. When you come back from vacation, make sure to plug your external drive back in BEFORE you turn your computer on.
When an external drive is plugged back in, it may take Backblaze a minute or two hours to schedule the files on the external drive to be backed up online.
Arq:
If the drive isn’t mounted, Arq just skips it.
I’m planning to use Arq to back up one of my external archive drives to Amazon Glacier. After considering the trade-offs, it seems to make sense to put this in a different backup set than my primary and auxiliary drives. I discussed this with Arq’s developer, and it sounds like it will be able to handle multiple current backup sets for the same Mac, although only one of them can be active at a time.
Update (2013-11-08): Using multiple Arq backup sets on the same Mac seems to not be as smooth as I’d hoped. For example, it does not always retain the proper S3 budget when switching between them.
4 Comments RSS · Twitter
Nice comparison ;-)
But for me the final decision was made by this one argument in favor of Backblaze: USD 5 per month. No matter how much data you upload. (And the external hd is attached to my Mac practically all the time.)
With Arq/Glacier: ~USD 45 per month.
[...] more flaws and design limitations become visible. For example, Backblaze is highly regarded, yet it silently deletes backups of external drives that haven’t been connected in a [...]
[...] previously been hesitant about Backblaze because of the way it handles external drives. I’ve read about problems with large bzfileids.dat files sucking RAM and [...]
