ODK Central storage

1. What is the problem? Be very detailed.
Can someone please advise me how ODK Central uses storage on DigitalOcean, and how to check how much storage is currently being used and how much more storage is available. I believe I should have ample storage available, but the DigitalOcean graph says that I've already used about 75% of available storage. I currently about 3.5GB of data on Central, based on the size of the Google Drive backup and confirmed by the size of downloaded data on my local drive. This is far below the 60GB disk + 100GB storage volume that I should have available.
2. What app or server are you using and on what device and operating system? Include version numbers.
ODK Central v.0.8 on Digital Ocean with 3GB memory/60GB disk, plus attached 100GB volume.

3. What you have you tried to fix the problem?
Upgraded to larger memory and disk; added Volume.

4. What steps can we take to reproduce the problem?
5. Anything else we should know or have? If you have a test form or screenshots or logs, attach below.
My survey data includes jpg media attachments, which account for most of the storage requirements. Since jpg is already a zipped format, the zipped data size is not much different from the unzipped size.

Central puts all its data in a PostgreSQL database managed by Docker. The relevant folder is in your Docker data directory, so likely /var/lib/docker/volumes/some-randomly-generated-uuid.

All this to say, your Central data is on your 60 GB boot disk, not the 100 GB disk you added. You'll need to move your data directory to the new disk.

I have not done this myself, but https://www.guguweb.com/2019/02/07/how-to-move-docker-data-directory-to-another-location-on-ubuntu seems like it'd work. Be sure to reboot after.

I'd strongly recommend doing a DigitalOcean snapshot of your machine before trying this move.

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Yaw, thanks for your help. I followed the directions you provided and successfully copied what I believe are the relevant files to the external 100GB volume, added the daemon.json file to the /etc/docker directory, and renamed the /var/lib/docker to var/lib/docker.old. However, then I could not log on to my Central page. I next tried to revert to the old setup by removing the daemon.json file and renaming docker.old back to docker, stopping and restarting the docker service, but unfortunately this former setup no longer allows me to log in either. So I'm stuck. I do have a snapshot, so if needed I could probably go back and start over, which would not be my first choice. Any help to get things up and running properly again would be greatly appreciated. Thanks in advance.
I'm attaching the json file and several screenshots:
daemon.json daemon.json (48 Bytes)
location of external volume List external volume 2020-08-15
files copied to external volume

When you say "unfortunately this former setup no longer allows me to log in either", I'm assuming you are referring to the Central login? What specifically happens when you try to login?

Have you tried a reboot? Also, what does docker ps show?

Hello again -- As you surmise, the problem was that my Central web page would not load at all, the connection just timed out. Following your hint, I shut down the droplet and restarted it. This solved the problem completely. Simply stopping and restarting Docker was not sufficient. I've documented the whole procedure to move docker data to an external drive, adding the reboot and a few other items that were missing from the link you provided or at least not obvious to me. If interested, I would be glad to send it in, suitably sanitized to remove references specific to my project. Many thanks for your help, and to you and the whole ODK team for your continuing work to support and improve this great system.


@Hayden_Boyd Thank you for your kind words. I'm glad it's working for you! If you can put your write up in a Google Doc (or Word or whatever) and email me at yanokwa@nafundi.com, I'll gladly integrate it into the Central docs.