In my last post, I talked about setting up an ODROID-HC2 as a NAS using OpenMediaVault. I have that up and running, and I’ve also written a few scripts to backup my data to a few of the SMB shares.

Now, I need to get that data shipped offsite to an external location to cover my 3-2-1 backup strategy:

  • 3 backups
  • 2 different types of media
  • 1 backup offsite


My cloud storage provider of choice is B2. I’ve written about them in the past and have generally had good luck with them, so I’d like to keep using them.

I was looking for software to transfer my backups to an offsite location, but it had it fit a few requirements:

  • work with B2 by default - B2 is object storage, so I can’t just push files to it via SSH or SCP, I need a client that can speak in B2’s HTTP API language
  • support encryption locally - because this data is going to be stored on devices not controlled by me, I wanted it to be encrypted locally before being sent to storage
  • open source - since this program is going to be encrypting my data, I want it to be auditable and trustworthy

While looking for backup programs, I compared the following:

I ended up choosing rclone for this task, instead of Duplicity. Duplicity is great, but it requires a good bit of memory to run, and it writes temporary files to local storage while it encrypts and uploads them. Because the ODROID-HC2 has limited hardware, I didn’t want this to become a problem. As far as I can tell, rclone doesn’t have these problems or limitations. In addition, this backup is really a backup of a backup, so I’m just interested in pushing large amounts of data offsite as quickly as possible, which rclone seems to be suited for.

Setup rclone

Install rclone

Rclone is available in the default Debian/Ubuntu repositories. However, the version is pretty out of date. On Ubuntu, you can add a PPA to get a newer version, but on Debian you can’t. Because of this, I recommend downloading the .deb directly from the rclone website.

sudo curl -sLO && sudo dpkg -i rclone-current-linux-arm.deb

Then, verify rclone is installed.

rclone -V

Configure rclone remote

Rclone uses a concept called remotes. Remotes are just remote storage locations, and you can nest remotes inside of other remotes.

First, configure rclone. It’s important to do this as the user that will be running rclone, so keep that in mind if you want to use a service account (more about this later).

rclone config

Press n to create a new remote.


Name the remote (I’m using backup01).


Press 3 to select B2 from the menu.


Enter your B2 account ID (you get this from B2’s control panel).


Enter your B2 application ID (you get this from B2’s control panel).


Leave the endpoint blank.

Press y to to save your configuration.


Configure rclone encrypted remote

Now, we’re going to created an encrypted remote inside of our first remote. Anything that goes into this encrypted remote will be encrypted automatically.

Press n to create a new remote.


Name the remote (I’m using backup01_crypt).


Press 5 to select crypt from the menu.


Enter the name of your rclone remote (e.g., backup01), followed by your B2 bucket name.


Press 2 to encrypt the file names.


Choose to create or generate a passphrase (I’m going to generate one).

Choose to create or generate a salt (I’m going to generate one).

Press y to to save your configuration.


Run backup

When you want to backup a file or directory, use the command below.

rclone sync /home/local/directory remote:bucket

In my case, the remote is backup01_crypt, and the bucket name is bucket01.

rclone sync /home/local/directory backup01_crypt:bucket01

Once the files are synced, you can list the files on the remote using the command below.

rclone lsf remote:bucket

In my case, the remote is backup01_crypt, and the bucket name is bucket01.

rclone lsf backup01_crypt:bucket01

ODROID performance

Overall, it look a little under 24 hours to do the initial transfer of around 580GB. During that time, my ODROID was hovering about 65-70°C.

CPU temp: 68°C

Also during this time, the ODROID-HC2 was using about 1GB RAM out of the available 2GB.

      total used free shared buff/cache available
Mem:   1993  965  209     51        818       921
Swap:   996   91  905

CPU usage hovered around 60% total capacity.

Load average: 0.59 0.56 0.71

A note about bandwidth

By default, rclone will transfer four files at the same time. If you want to change this number, you can use the --transfers flag. Obviously, if you have the hardware to support it, you can increase this number, which will decrease the amount of time it takes to complete your transfers, at the cost of CPU, memory, and bandwidth.

rclone --transfers=6 sync /home/local/directory backup01_crypt:bucket01

My internet connection is Verizon FiOS 100/100Mbps. I found that when using the default of four transfers at once, my bandwidth usage was about 60-80Mbps. However, when I kicked the transfers up to six, my bandwidth was 100% utilized at 100Mbps. This does decrease transfer time, but the internet in my house was almost unusable because the connection was saturated. Just something to keep in mind.

Backup your config file!

By default, rclone stores all of your B2 account information, your password, salt, and settings in the ~/.rclone.conf file of the account you used to configure rclone. If you lose this file, you lose access to all of your backups. Obviously, backup this file, but don’t save the backup on your encrypted storage.

Helpful commands

I’ve tried to gather some of the most useful commands from rclone’s website.

Command Description
rclone listremotes List all remotes
rclone config show remote Show config for a remote
rclone size remote:bucket Show total size and number of objects on remote
rclone ls remote:bucket List objects on remote
rclone lsd remote:bucket List directories on remote
rclone ncdu remote:bucket Like NCDU, but for your remote. Useful for seeing what is taking up disk space
rclone mount --read-only remote: /path/to/local/directory Mount your remote in a read-only state on a local directory
rclone tree remote:bucket Like tree Caveat - if filenames are encrypted, it will show them as encrypted
rclone serve http remote:bucket --addr :8080 Start a HTTP server to browse the remote, listen on all IPs on port 8080. Caveat - if filenames are encrypted, it will show them as encrypted
rclone sync /home/local/directory remote:bucket Copy source to destination, but do delete files in the destination if they were deleted from source (like the --delete flag in rsync)
rclone copy /home/local/directory remote:bucket Copy source to destination, but do not delete files in the destination if they were deleted from source
rclone cleanup remote:bucket Delete old versions of files stored on the remote

Hope this helps!



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