Time machine backup on S3
I've used arq for years and love it. It is not timemachine (bummer) but does do automatic backups to either Amazon's S3 or Glacier.
Update
As of 5/4/2015, Arq supports incremental backups the following services:
- Amazon s3 and Glacier
- Google Drive
- Microsoft OneDrive
- DropBox
- Google Cloud Storage
- SFTP to your own server
- DreamObjects
- Other S3 compatible services
Using AWS S3 as the storage of Mac Time Machine definitely works now.
Time Machine can backup the data to external device, so the key is mounting S3 bucket as a POSIX FS in Mac.
There are many tools or solutions to support mounting S3 like a local device in MacOSX, such as S3fs, Goofys. Juicefs is a personal recommended SaaS which provides 1TB free quota.
Once you mount the S3 bucket as local device whatever above tools you prefer, you can follow this guide to create a sparse image in S3 mount point(actually it's created in S3 bucket) as the destination of time machine backup.
Also you are recommended to enable S3 IA or intelligent tier for saving cost. You can also use KMS to encrypt the backup data stored in S3.
Edit: I tried this and it didn't work. (Time Machine cannot see the mounted volume/bucket.)
You may be able to use Panic's Transmit app to [mount an S3 bucket as a local Volume][1] and then point Time Machine to that mounted volume as the destination.
I haven't tried this yet, but I plan to.
[1]: https://library.panic.com/transmit/td-install/