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Knowledge Center

How to differentiate system modes of your Synology NAS by LED indicator statuses

Last updated:Dec 6, 2021

How to differentiate system modes of your Synology NAS by LED indicator statuses

Purpose

Understanding the boot process and LED status of the Synology NAS is important in identifying hardware failures of your device. This article introduces the LED behavior status at each stage of the Synology NAS power-on process. For more information, refer to the hardware installation guide for your specific model.

Environment

  • Applicable for all models released in 2015 and later.
  • Applicable for DSM 6.2.4 and later.

Contents

Resolution

System mode identification by LED

System modes can be identified through the POWER and STATUS LED indicators. Please refer to below tables for more details.

Models without Alert LED1

System mode LED indicator
POWER STATUS
Blue or Green Green Orange
Powering on Blinking Off Off
Shutting down2 Blinking Static Off/Static
DSM not ready Static Blinking Off/Blinking
DSM is ready for use Static Static Off/Static
Hibernation Static Off Off/Static
Application Static Switching
Powered off Off Off Off

Models with Alert LED3

System mode LED indicator
POWER STATUS
Blue or Green Green Orange
Powering on Blinking Off Off
Shutting down Blinking Static Off
DSM not ready Static Blinking Off
DSM is ready for use Static Static Off
Hibernation Static Off Off
Application Static Switching
Powered off Off Off Off

System mode definitions

System mode Definition
Powering on Synology NAS is powering on when you press the power button or restarting when you run operations in DSM. During the boot up process, the device also performs hardware initialization, such as hardware reset or BIOS initialization.
Shutting down Synology NAS is shutting down when you press the power button or run operations in DSM.
DSM not ready DSM is not ready for use. This could either be:
  • Synology NAS is powered on, but DSM is not properly installed.
  • Synology NAS is currently powering on and initializing services necessary for DSM to fully function.
  • The attached UPS device has insufficient power; DSM stops all services to prevent data loss (enters safe mode).
DSM is ready for use DSM is fully functioning and users can sign in.
Hibernation Synology NAS has been idle for a while and is now in Hibernation mode.
Application Certain packages/services (e.g., USB Copy and Find me service) while in operation will control the actions of the LED. After the operation is complete, the LED indicator will return to its normal state.
Powered off Synology NAS is powered off.

Transition between system modes

To better understand the transition between system modes, please refer to below examples:

  • Powered on with no DSM installed:

    Powered off > Powering on > DSM not ready

  • Powered on with DSM installed:

    Powered off > Powering on > DSM not ready > DSM is ready for use

  • Enter hibernation then wake up from hibernation:

    DSM is ready for use > Hibernation > DSM is ready for use

  • Shutdown Synology NAS:

    DSM is ready for use > Shutting down > Powered off

  • Power failure with UPS attached:

    DSM is ready for use > DSM not ready (due to power failure, DSM enters safe mode) > Shutting down > Powered off > Powering on (power has recovered, DSM will reboot) > DSM not ready > DSM is ready for use

DSM boot process flow

The following table provides detailed information for each system mode during the boot process of the Synology NAS. For other system modes and definitions, please refer to the Hardware Installation Guide for your specific model.

System mode DSM 6.2.3 and below DSM 6.2.4 and above Stage4
Powering on Power: Blinking Blue
Status: Off		 Power: Blinking Blue
Status: Off		 Powering on
Hardware initializing
BIOS
Bootloader
DSM not ready Power: Static Blue
Status: Blinking Orange		 Power: Static Blue
Status: Blinking Green		 Linux kernel
DSM ready for use Power: Static Blue
Status: Static Green or Blinking Orange		 Power: Static Blue
Status: Static Green or Static Orange		 DSM ready

LED indicator behavior differences

LED behaviors will differ between DSM versions and models because when the Linux kernel is loaded, the power indicator turns a static blue, and simultaneously, the status indicator turns a flashing green. The following flowchart illustrates the differences in the behavior of the LEDs during power-up.

Notes:

  1. If the STATUS LED remains static orange or continuously blinks orange when DSM is ready, it indicates a system error such as fan failure, system overheating, or volume degrade/crashed. Please sign in to DSM for more information.
  2. The POWER LED indicator may continuously blink if your device encounters issues while shutting down. Please sign in to DSM for more information.
  3. If the ALERT LED remains static orange or continuously blinks orange when DSM is ready, it indicates a system error such as fan failure, system overheating, or volume degrade/crashed. Please sign in to the DSM for more information.
  4. Detailed descriptions of each stage are listed in the below table:
    Stage Description
    Power on Power button is pressed.
    Hardware initializing DC power is supplied to all hardware devices such as Motherboard, HDD, CPU, Memory, Controllers, NIC, etc.
    Controllers (SATA/NIC) are initialized.
    BIOS CPU loads BIOS.
    BIOS initializes PCIe, memory, etc.
    BIOS loads bootloader (GRUB) from flash (synoboot).
    Bootloader Bootloader loads Linux kernel image into memory and passes control to the Kernel.
    Linux kernel Linux kernel initializes RAM file system (initrd) and loads driver modules.
    Linux kernel detects RAID on HDD and assembles md0 (root partition).
    DSM startup Initializes DSM, the library, and services are started.
    DSM UI is ready.
    DSM ready DSM is fully functional and users can sign in.

Further reading

Purpose
Environment
Contents
Resolution
System mode identification by LED
Transition between system modes
DSM boot process flow
LED indicator behavior differences
Further reading