Volumes
Understand volume types, mounting, and how Zerobyte connects to your data sources
Volumes are the data sources you want to protect with Zerobyte. Each volume represents a filesystem, such as a local directory, a network share, or a remote storage location, that Zerobyte mounts and reads from when running backups.
What are volumes?
A volume tells Zerobyte where your data lives. When you create a volume, you provide connection details (a path, a server address, credentials) and Zerobyte takes care of mounting that filesystem, monitoring its health, and making it available to your backup jobs.
Volumes support a range of protocols, from simple local directories to NFS shares, Windows/Samba file servers, WebDAV endpoints, SFTP connections, and cloud storage via rclone. Once a volume is mounted, you can browse its contents directly in the UI, assign it to one or more backup jobs, and let Zerobyte handle the rest.
Mounted remote volumes can expose translated metadata instead of the source system's original ownership and ACL model. Before relying on NFS, SMB, WebDAV, SFTP, or rclone volumes for metadata-sensitive backups, read Mounted Shares, ACLs, and Metadata Fidelity.
Supported volume types
Zerobyte supports six volume types. Each one is configured through the web UI when you create or edit a volume.
Directory (local)
A local directory on the host machine, mounted into the Zerobyte container via your compose.yaml file.
Use cases:
- Backing up application data, configuration files, or databases on the host
- Testing backup configurations before adding remote volumes
- Protecting Docker volume data or bind-mounted directories
Form fields:
- Name, a descriptive label for this volume
- Path, the path inside the container where the directory is mounted (e.g.,
/data)
You must first mount the host directory into the Zerobyte container by adding it to the volumes section of your compose.yaml. For example, to back up /home/user/photos on the host, add - /home/user/photos:/photos:ro to your compose file, restart the container, then create a Directory volume in the UI with the path /photos.
Volume status
Every volume is in one of three states, visible at a glance in the Volumes list.
Mounted
The volume is connected and accessible. Backup jobs can read from this volume.
Unmounted
The volume exists in Zerobyte but is not currently connected. Backups that depend on this volume will not run until it is mounted again.
Error
Something went wrong, the mount failed, the network is unreachable, or credentials were rejected. The volume detail view shows the specific error message. If auto-remount is enabled, Zerobyte will attempt to recover automatically.
Auto-remount
Auto-remount is enabled by default for every volume. When a mounted volume enters an error state (for example, due to a temporary network outage or a server restart), Zerobyte automatically attempts to re-establish the connection without any manual action.
This is especially valuable for network-based volume types (NFS, SMB, WebDAV, SFTP, Rclone) where transient connectivity issues are common. Auto-remount ensures your scheduled backups continue to run even after brief disruptions.
You can disable auto-remount for any volume if you prefer to handle reconnections manually.
File browsing
Once a volume is mounted, you can browse its contents directly from the Zerobyte web interface. File browsing lets you:
- Verify that the volume mounted correctly and points to the expected data
- Explore the directory structure to identify paths you want to include or exclude in your backup jobs
- Confirm that the files and folders you need to protect are accessible
This is a read-only view of the volume's contents, browsing does not modify any files.
Read-only mode
All six volume types support mounting in read-only mode. When enabled, Zerobyte can still read and back up files, but write operations are blocked at the filesystem level.
Read-only mode adds an extra layer of safety when backing up production data. It guarantees that the backup process cannot accidentally modify or delete source files.
Credential security
Sensitive fields, such as passwords, private keys, and other secrets, are encrypted before they are stored. Zerobyte never saves credentials in plain text.
Provisioned volumes also support secret references:
env://VARIABLE_NAME, resolves the value from an environment variable set in yourcompose.yamlduring provisioningfile://secret_name, resolves the value from a Docker secrets file at/run/secrets/secret_nameduring provisioning
During provisioning, Zerobyte resolves these references on startup and stores the resolved value encrypted in the database.
The regular volume form in the UI currently expects the actual credential value. Entering env://... or file://... there will not resolve it at runtime.
For a complete walkthrough of managing secrets through environment variables, Docker secrets, and provisioning files, see the Provisioning guide.