When will online-only files work on Linux?

For anyone wanting to have something like smart sync (e.g. a mounted point that only loads files as neccessary) there is the option of using rclone . This is a tool that supports multiple remote file systems and has lots of utilities for interacting with them.

In particular you can use "rclone mount" to mount your dropbox to some folder.

For example:

mkdir ~/dropbox
rclone mount dropbox:/ ~/dropbox

Will allow you to access your dropbox remote via the folder ~/dropbox .

Now there's a few options we'll want:

--dir-cache-time 30s # Ensures entering a folder that was really recently entered doesn't need reload time
--cache-dir ~/.rclone-cache-dir/ # Allows files to be cached instead of being loaded every time
--vfs-cache-max-age 24h # Allows you to set time files will be kept in cache until they're removed from disk, configure to whatever you want
--vfs-cache-max-size 2G # Allows you to set how much space will be used for cache, configure to whatever you want
--vfs-cache-mode full # Ensures writes and reads are buffered to disk before sync

Now this gives a pretty good mounted fs however unfortunately this will not mount automatically on login.

In order to get it working on startup we can use systemd to configure session start tasks.

So create file:

~/.config/systemd/user/rclone-mount-dropbox.service

Now in this file we'll add our startup config:

[Unit]
Description=Rclone Dropbox
Wants=network-online.target
After=network-online.target

[Service]
TimeoutStartSec=60
ExecStartPre=/bin/mkdir -p /home/<username>/dropbox
ExecStart=/usr/bin/rclone mount dropbox:/ /home/<username>/dropbox --dir-cache-time 30s --cache-dir /home/<username>/.rclone-mount-cache/ --vfs-cache-max-age 24h0m0s --vfs-cache-mode full --vfs-cache-max-size 2G
ExecStop=-/usr/bin/fusermount -u /home/<username>/dropbox
Restart=on-abort

[Install]
WantedBy=default.target

Configure the options for the cache however you want. Make sure to change /home/<username> to whatever your home directory in all places it appears in the command.

Now to add the service to run automatically:

systemctl --user enable rclone-mount-dropbox.service

And that's it, restart your computer (or start the service with systemctl) and voila you have a mounted dropbox in your home directory.