Offsite Disk Farm

The provider has a small, cheap computer with a lot of disk space and a fast network connection. You pay a monthly fee for the privilege of keeping a copy of your entire filesystem on the provider's disk. Every day, you use rsync to bring the remote copy up to date.

Then, if you had a catastrophic disk failure, or a fire, you just go out and buy new equipment, download a complete copy of all your files from the remote site, and pick up where you left off. There's no need to even configure a new operating system. You could even have a special "disaster" floppy that would reinstate the entire system when you booted from it.

Some numbers: I have about 20GB of disk here. On a typical day, I would need to rsync 35-40MB of data to update the remote copy. A substantial part of this is just bringing my web browser cache up to date, and could be skipped if I wanted. My cheap DSL connection requires about an hour and a half to upload 40MB of data and about four days to download 20GB.

If you don't want to wait four days, and you can't get a faster network connection, you have an alternative: Keep spare hard disks at the provider's offices. If there's a disaster, they take your hard disks off the shelf, copy your data onto them, and have them sent to you by fast courier. Then you plug them in and pick up where you left off. Or perhaps the provider doesn't have extra disks; perhaps they were storing your data on your disks all along.