Unfortunately there is no backup silver bullet, so to ensure that I have the computers in my home backed up and secured I use a mix of services. In the following sections I will describe how I use Time Machine, Arq and GitHub to keep my data backed up and secure.
Time Machine and Drobo
I use Time Machine to fully backup 3 MacBooks and a MacMini to a Drobo that is attached to the MacMini.
"The longer Time Machine is used, the more data storage it requires. Unlike other protected storage arrays, Drobo uses patent-pending BeyondRAID software that is designed for non-technical users who demand both reliability and instant expandability without the complexity of traditional RAID." - Drobo Site
The Drobo provides the ability to "Hot Swap" drives if they fail or if space is running out.
If a hard drive fails in any of my computers I can restore from Time Machine in a couple of hours.
The Time Machine solution makes it easy to do full backups and is trivial to setup.
Thanks to the reliability of Drobo, and the daily incremental backups to it via TimeMachine, the only way to have data loss is if the computers and Drobo are stolen or somehow destroyed (e.g. by fire). So for a subset of data that I deem most critical, and that would not be recoverable if I lost both my computers and Drobo, I use Arq.
I use Arq to back up my most critical files to Amazon S3. Amazon S3 is a "highly scalable, reliable, secure, fast, and inexpensive infrastructure" that Amazon uses for its own applications.
Arq backups are complete and accurate, including all "metadata". I do an incremental backup every night on my main computer's home directory (with a few exceptions - see the final section). My current backup size is 66GB and I transfer about 400MB-700MB per night. This works out at a monthly cost of less than $4.
The speed of transfer to S3 is amazing. It is almost as fast as the backup to Time Machine (and the size is usually the same). If I could afford to fully backup my computers to S3 I would and then maybe I could do away with Time Machine.
Arq also encrypts the data that is stored on S3. I use a generated password to access my S3 account. The data is encrypted with a generated key. The Arq program remembers this information so I do not need to remember the keys. However since these are complicated password/keys that I do not memorize I need a place to store them securely. And of course I will need access to this if I do not have my computers or Drobo. For this I use 1Password and DropBox.
1Password is a password management tool that stores all my passwords. I just have to remember one password to unlock the app and I can retrieve any of my passwords. It also has built in browser support so you can easily sign into websites or enter credit card information online.
One of its best features is that you can store the encrypted password file in a shared folder and access it from multiple computers. This way all your computers have all your latest passwords.
Since I often have my laptop offline or not on my home network I always want a local copy of this password file. To do this I use DropBox.
DropBox allows you to replicate a folder on your computer to their cloud. With this I replicate the folder across all my computers and it manages keeping them in sync. 1Password also ensures that if you were accessing the password file from multiple computers at once that the data is not corrupted.
One nice addition to using 1Password and DropBox is that there that 1Password has an iPhone app that has support for connecting to DropBox also. So now I also have all my passwords on my iPhone too.
Excluded from Backup to Amazon S3
I keep all my Github repositories in my ~/Development directory and always try to keep my work pushed to Github. If I have work in progress changes I usually push them to a branch off of master. Because of this I do not backup my ~/Development directory to [Amazon S3]](http://aws.amazon.com/s3/) since it is redundant. The size of some of my repositories is large too so this is a good thing.
Similarly I have my music replicated over a few computers, iPods, etc. So I do not back this up either to Amazon S3.
I also have a Flickr Pro account that I store all my photos on so I do not backup my Pictures folder to Amazon S3 either.
There are a number of other folders I exclude that are application related
since I can always reinstall the applications (e.g. Library/Caches, Library/Logs, Dropbox, Downloads).