synodeb turns a Synology NAS into a plain Debian trixie server. A Linux kernel (6.18 LTS, or the newest stable 7.3) with drivers for the NAS is started by its own boot loader, and the official Debian installer runs over SSH. You choose disks, RAID, LVM and filesystems as on any Debian machine. DSM can stay on its own disks, and one command switches between the two.

This project is not affiliated with, endorsed or supported by Synology Inc. "Synology", "DiskStation" and "DSM" are trademarks of Synology Inc.

More models are planned in #7: if you own one and want to help, say hello there.

• Boot from the internal DOM through the Synology boot loader; DSM stays bootable.
• Disks: every SATA bay with DSM-style staggered spin-up, hot-plug and activity LEDs; both NVMe slots with the DSM power limit.
• Network: the onboard ports; on the DS923+ also the E10G22-T1-Mini 10 GbE card.
• Front panel: power and status LEDs, beeper, power button (clean shutdown), reset button.
• Fans on the DSM curves, with failure alerts.
• Power: power off and reboot, power on after an AC loss, scheduled power on, hardware watchdog.
• UPS over USB with a DSM-like Safe Mode; optional network UPS server.
• Kernel updates from the synodeb apt repository; a kernel that does not boot falls back to the previous one by itself.
• Notifications by e-mail, Telegram or ntfy (SMART, RAID, fans, UPS, failed services).
• DSM volumes readable from Debian, to copy the data over.
• Hardware video transcoding on the DS920+ (Intel iGPU, VA-API/QSV).

You need DSM 7 with SSH enabled (Control Panel → Terminal & SNMP), an administrator account and internet access.

1. Back up your data.

2. On DSM, over SSH:

   curl -fsSLO https://raw.githubusercontent.com/rylos/synodeb/main/synodeb-setup.sh
   sudo bash synodeb-setup.sh install

   It backs up the DOM, asks before writing it and prints how to connect to the installer. Copy the DOM backup off the NAS.

3. Reboot (sudo reboot). After 2-3 minutes one long beep: the installer is ready.

4. Connect with the command and one-time password the script printed, choose Start installer and install Debian. Leave the DOM (the 128 MB disk) alone; to keep DSM, install on a disk DSM does not use.

5. The NAS reboots into Debian: ssh <user>@<address>.

Until the installation completes, any reboot brings DSM back. Details, partitioning advice and troubleshooting: docs/install.md.

Switching: from Debian sudo synodeb-dom default dsm && sudo reboot, from DSM sudo bash synodeb-setup.sh boot debian && sudo reboot.

• Installation: steps, choosing disks, keeping DSM, synodeb-setup.sh
• On the installed system: commands, configuration, UPS, notifications
• Kernel: series, updates, headers and DKMS
• How it works and building: DOM, drivers, build, CI, models
• Serial console, for debugging
• Hardware notes per platform: r1000 (DS923+, DS1522+), geminilake (DS920+)

• No root on an encrypted volume (it cannot be unlocked without a console); encrypt data volumes instead.
• ZFS only with the longterm kernel.
• Expansion units (DX517 and others): experimental driver, not confirmed on these models.
• The NAS is reached over the network only; the serial console is for debugging.

Problems go to the issues, questions and ideas to the discussions.

• abb-agent: an agent for Synology Active Backup for Business that runs on any Linux distribution and kernel, with no kernel module to build.

synodeb is developed in spare time. Supporting more models needs the hardware to test on, and donations go towards that. You can buy me a beer 🍺 at this Ethereum address (ETH or any token on Ethereum and on networks with the same addresses: Base, Arbitrum, Optimism, Polygon, BNB Chain…):

0xF4dd2D015b913E30429974c2b82e15df5b92fB19

GPL-2.0-only. See LICENSE.