General settings: Change web interface listening port, SSL and force SSL. Change admin password.
Notification system: Integrated into several services in the form of email using Postfix  backend as MTA, these include scheduled tasks, services monitoring, S.M.A.R.T., MDADM and cron-apt. Since openmediavault 3.0 is possible to add also third party notification systems by using scripts, more information here and real example on how to use it here.
Network configuration: The web interface provides configuration options for ethernet, WiFi (only WPA/WPA2 supported), bond and vlan interfaces. This also includes a panel for firewall configuration.
Certificates: Create or import existing SSL and SSH certificates. This certificates can be used for securing the web interface or SSH access. Plugins can use the backend framework to select the available certificates. Automatic scheduled tasks that check for expired SSL certificates, including notification by email.
Power Management: Scheduled power management for hibernation (S5), suspend (S3), shutdown and/or reboot.
Service Discovery: Using avahi-daemon  is possible to announce the following services Samba, NFS, AFP, FTP, web admin panel, to any Linux desktop with file browser that supports it (GNOME, KDE or XFCE for example). OS X can recognise AFP and Samba services in the Finder sidebar. To announce SMB to windows clients, samba uses NetBios, not avahi.
Scheduled Tasks: Based on cron the webUI can define tasks for running specific commands or custom scripts at certain time or regular intervals.
Update Manager: Displays all available packages for upgrade. Automatic daily tasks to check for updates, including notification by email. Security updates will be installed unattended.
S.M.A.R.T.: Based on smartmontools , It can display advanced information of S.M.A.R.T values in the webUI. It can also schedule health tests as well as send notifications when S.M.A.R.T. attributes values change.
RAID Management: Based Linux RAID , create arrays in 6 different configurations. Levels available are linear, 0, 1, 10, 5 and 6. The array can have disks removed or expanded using the web interface.
File Systems: Volume format, device mount and unmount. More information in the filesystem section.
LVM: Enhanced by the LVM2 plugin, the system has the capability of formatting disks or partitions as LVM that can be used in volume groups to create logical partitions.
Shared Folders: Simple shared folder administration. Within this section is also possible to assign ACLs and/or privileges to the shared folders. Snapshots can be taken manually or via scheduled tasks for shared folders that are located on Btrfs file systems. Automatic scheduled tasks for Btrfs file systems to scrub them and check for errors, including notifications via email.
Users: User and group managing. Using privileges is possible to restrict access/login to shares on network sharing services (FTP, Samba and AFP) without interfering Unix permissions. Automatic scheduled task that checks for locked/banned users, including notification by email.
Groups: Create and manage custom groups. System groups cannot be manipulated here.
SMB/CIFS: SMB sharing protocol using Samba  as standalone server by default.
FTP: Service based on proftpd . Intended for accessing shares from remote or local.
This service has been removed from core in openmediavault version 6. It can be installed as plugin now.
RSync: Server daemon. Shared folders can be defined as rsyncd modules. With scheduled tasks, rsync client can be configured for push or pull jobs.
NFS: Network file system protocol .
SSH: Remote shell access using openssh .
TFTP: A basic configuration panel is provided. This can complement a PXE server to deploy local network installations.
This service has been removed from core in openmediavault version 4. It can be installed as plugin now.
Dashboard: By default the server comes with four information widgets. Network interfaces, System, Filesystem and service/daemon status. The dashboard panel can have widgets added using the plugin framework.
System information: The panel displays four tabs with system information and statistics graphs.
System Logs: Interface to view and download logs from syslog, journalctl, message, auth, ftp, rsync and samba. Plugins can attach their logs here using the framework.
Services: View status (enabled/disabled and running/not running) of services. Detailed information is provided by default for Samba, FTP and SSH. Plugins can use this tab to integrate their service information also.