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Backing up to DreamObjects with Duplicity

Backing up to DreamObjects with Duplicity thumbnail

The other day I was talking with my wife and she revealed a dirty little secret. She had not backed up the pictures on her phone or camera since our daughter was born in August. Meet Chloe!

Baby Chloe

It’s really more my fault than hers. I’m the one that works with technology professionally. And I certainly know a thing or two about backing things up as one of the system engineers that helped create DreamObjects, a cloud storage service here at DreamHost.

I decided that I wanted to use a product I helped build to archive my family’s growing collection of memories because I’m extremely confident about its durability. DreamObjects uses open-source storage software named Ceph that began as a Ph.D. thesis for one DreamHost’s co-founders Sage Weil. After years of being an exciting research project and continued development here at DreamHost, Ceph is now running in production and trusted by an ever-growing number of customers. Ceph uses the CRUSH algorithm to replicate data N times (currently we set this to 3) across racks and racks of servers according to a placement map that assures availability despite the loss of various common failure domains eg. a server, a rack or in our design an entire row of servers.

Many people use FTP to upload files to their hosting account at DreamHost (it’s not called file transport protocol for nothing). DreamObjects is a bit different in that you can’t use FTP, SFTP, or SSH to copy files to the service. Don’t worry, that doesn’t mean you have to know a programming language in order to use it! DreamObjects provides several RESTful APIs, one that is compatible is Amazon S3 and another that is compatible with OpenStack Storage (Swift). There are a lot of tools that are readily available and work with compatible services like DreamObjects. After a bit of research and talking with co-workers I decided that I wanted to try using Duplicity since it has a lot of things that appealed to me:

  • Open Source (free as in speech and free as in beer)
  • Encryption
  • Incremental backups

I’ve always been a huge fan of open-source software and certainly don’t mind digging through code on occasion. The freedom to understand how an application works and modify it if the need arises is invaluable. Anyone that has been around me for a while knows that I’m a bit paranoid when it comes to security. I use whole disk encryption, put anti-virus software on my Macs, PGP sign every email I send and slather every Linux kernel within arms reach with a copious amount of grsecurity. Incremental backups are fantastic if you want to continue to backup your ever-growing collection of digital media without performing a complete backup each and every time.

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Getting Started

I’m setting up backups for a Mac in this article although the setup would be almost identical if you’re running Linux on your desktop or if you were backing up your site from one of our shared hosting, VPS, or dedicated servers. First, you will need to set up a plan for DreamObjects; if you already have an account with us you can do so from the panel here, otherwise, you can signup and then head over to the panel. Once you have a plan you will want to create a user, and after submitting a username you’ll have to periodically refresh the page to see if it is now available. Now once you have a DreamObjects user you will want to click the “1 keys” button on the right side and copy down the user key, followed by revealing the secret key and copying that.


Since we need to build the duplicity application we need to install a couple development utilities. The first tool you will need is Xcode, it’s available for download from the Mac App Store. The next tool you need to install is a package manager called homebrew, paste their one-liner to Terminal:

ruby -e “$(curl -fsSkL”

Your getting closer! Now that you have Xcode and homebrew you are ready to install the dependencies for duplicity. In the same Terminal paste the following:

brew install librsync python gpg ncftp

Once homebrew finishes doing what it does best you’ll finally be ready to download Duplicity. Afterward, extract it by using this command in Terminal:

tar xvzf duplicity-0.6.20.tar.gz

Now it’s time to install python libraries and build duplicity, again paste the following into the terminal:

pip install boto httplib2 oauth
cd duplicity-0.6.20
sudo python install

Now we have to take our user and secret key and put them into a file named ‘.boto’ in our users home directory. You can do this with the following commands if you substitute your own keys:

echo “[Credentials]” >> ~/.boto
echo “aws_access_key_id = 98F3n8qUtWEJ6ZdBYyQy” >> ~/.boto
echo “aws_secret_access_key = p5kptXKQrsQtTNJTYtG7emGYooXkN6Kaza1OV-_s” >> ~/.boto

Now you can backup any directory you desire to a bucket name of your choice. In this example, I’m backing up my Pictures directory to the blogdemo bucket:

duplicity –allow-source-mismatch ~/Pictures \

It prompts for an encryption password, which you won’t want to forget, and then syncs your files. The output should look something like this:

GnuPG passphrase:
Retype passphrase to confirm:
No signatures found, switching to full backup.
————–[ Backup Statistics ]————–
StartTime 1356046824.18 (Thu Dec 20 15:40:24 2012)
EndTime 1356046824.20 (Thu Dec 20 15:40:24 2012)
ElapsedTime 0.02 (0.02 seconds)
SourceFiles 10
SourceFileSize 374 (374 bytes)
NewFiles 10
NewFileSize 374 (374 bytes)
DeletedFiles 0
ChangedFiles 0
ChangedFileSize 0 (0 bytes)
ChangedDeltaSize 0 (0 bytes)
DeltaEntries 10
RawDeltaSize 0 (0 bytes)
TotalDestinationSizeChange 295 (295 bytes)
Errors 0

That’s it! You’ll want to run this command whenever you want to update your backups. I prefer to run it manually when I’m importing pictures, but it wouldn’t be difficult to configure Cron to automatically backup a directory on your computer.


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1 Comment

  1. I think I’m lost. I’m trying to find how to backup Dreamhost shared hosting files to DreamObjects automatically or if there’a UI inside But I guess there’s no quick way but follow the instructions you wrote via xcode + homebrew + python libraries then build duplicity. O__O

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