Synology NAS RS2421+ Manual
Synology NAS RS2421+/RS2421RP+
Hardware Installation Guide
Table of Contents
Chapter 1: Before You Start
Package Contents 3
Synology RS2421+/RS2421RP+ at a Glance 4
System Modes and LED Indicators 6
Other LED Indicators 8
Hardware Specication 9
Spare Parts 10
Optional Accessories 10
Safety Instructions 11
Chapter 2: Hardware Setup
Tools and Parts for Component Installation 12
Install Drives 12
Install Memory Modules 14
Install a PCle Add-in Card 17
Install and Remove Rail Kits 18
Expansion Unit Deployment and Topology 20
Start up Your Synology NAS 21
Chapter 3: System Maintenance
Replace System Fan 22
Replace Power Supply Unit (PSU) 23
Chapter 4: Install DSM on Synology NAS
Install DSM with Web Assistant 24
Learn More 24
Synology_HIG_RS2421(RP)+_20201222
2
Thank you for purchasing this Synology product! Before setting up your new Synology NAS, please check the
package contents to verify that you have received the items below. Also, make sure to read the safety instructions
carefully to avoid harming yourself or damaging your Synology NAS.
Note: All images below are for illustrative purposes only, and may dier from the actual product.
Package Contents
Main unit x 1 AC power cord1
Screws for 2.5” drives x 52
Screws for 3.5” drives x 52
Before You Start 1
Chapter
3
1AC power cord: RS2421+ x1; RS2421RP+ x2
4Chapter 1: Before You Start
Synology RS2421+/RS2421RP+ at a Glance
6
1
5
2 3 4
7 7
RS2421+
8
11 10
14 1513
12
17
16
RS2421RP+
8 10
14 1513
129
16 17
No. Article Name Location Description
1 POWER Button
and Indicator
Front
1. Press to power on your Synology NAS.
2. To power o your Synology NAS, press and hold until you hear
a beep sound and the Power LED starts blinking.
2 STATUS Indicator Displays the status of the system. For more information, see
"System Modes and LED Indicators".
3 ALERT Indicator Displays warnings regarding fan or temperature. For more
information, see "Other LED Indicators".
4 Beep O Button Press to deactivate the beep that sounds when a malfunction
occurs.
5 Drive Tray Install drives (hard disk drives or solid state drives) here.
6 DRIVE Status
Indicator
Displays the status of drive. For more information, see "Other
LED Indicators".
7 Rail Kit Release Tab Push in and hold to release your Synology NAS from a rail kit
lock.1
1For more information about the rail kit installation, please refer to the Quick Installation Guide that comes with the rail kit.
5Chapter 1: Before You Start
No. Article Name Location Description
8 Power Port
Rear
Connect power cord here.
9 PSU Indicator and
Beep O Button
1. Displays the status of the power supply unit (PSU). For more
information, see "Other LED Indicators."
2. Press to deactivate the beeping sound that is emitted when a
malfunction occurs.
10 PSU Fan Disposes of excess heat and cools the PSU.
11 Power Supply On/O
Switch Press to turn on/o the power supply.
12 Console Port This port is used for manufacturing only.
13 1GbE RJ-45 Port Connect RJ-45 network cable here.
14 USB 3.2 Gen 1 Port Connect external drives or other USB devices to the Synology
NAS here.
15 Expansion Port Connect to Synology Expansion Unit2here.
16 RESET Button
1. Press and hold until you hear a beep sound to restore the IP
address, DNS server, and password for the admin account to
default.
2. Press and hold until you hear a beep, then press and hold again
until you hear three beeps to return the Synology NAS to “Not
Installed” status so that DiskStation Manager (DSM) can be
reinstalled.
17 PCI Express
Expansion Slot Supports the addition of PCIe network interface cards.
2For more information about Synology Expansion Unit supported by your Synology NAS, please visit www.synology.com.
6Chapter 1: Before You Start
System Modes and LED Indicators
System Modes and Denitions
There are 7 system modes in Synology NAS. The System modes and their denitions are as below:
System mode Denition
Powering on Synology NAS is powering on and performing hardware initialization, such as
hardware reset or BIOS initialization.
Shutting down Synology NAS is shutting down as a result of pressing the power button or operation
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 insucient 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 o Synology NAS is powered o.
Identify System Modes
You can identify the system mode through the POWER and STATUS LED indicators. Please refer to below table
for more details.
System mode
LED Indicator
POWER STATUS
Blue Green Orange
Powering on Blinking O O
Shutting down Blinking Static O
DSM not ready Static Blinking O
DSM is ready for use Static Static O
Hibernation Static O O
Application Static Switching
Powered o O O O
7Chapter 1: Before You Start
Transitions between System Modes
To better understand the transition between system modes, please refer to below examples:
• Powered on with no DSM installed:
Powered o > Powering on > DSM not ready
• Powered on with DSM installed:
Powered o > 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 o
• Power failure with UPS attached:
DSM is ready for use > DSM not ready (due to power failure, DSM enters safe mode) > Shutting down >
Powered o > Powering on (power has recovered, DSM will reboot)> DSM not ready > DSM is ready for use
8Chapter 1: Before You Start
Other LED Indicators
LED Indicator Color Status Description
DRIVE status Indicator
(on tray)
Green
Static Drive ready and idle
Blinking Accessing drive
Red Static Drive error/Port disabled1
O No internal Drive
ALERT
Orange Blinking System error2
O System normal
PSU Indicator3
Green Static Power supply unit normal
O Power supply unit o
Rear 1GbE LAN
(on left side of jack)
Green
Static Network connected
Blinking Network active
O No network
Rear 1GbE LAN
(on right side of jack)
Green
Static
1 Gbps connected
Orange 100 Mbps connected
O 10 Mbps connected/No network
Note:
1 Please try to restart your Synology NAS or re-insert the drives, then run the HDD/SSD manufacturer's
diagnostic tool to check the health status of the drives. If you can sign in to DSM, please run the built-in
S.M.A.R.T. test to scan the drives. If the problem remains unresolved, please contact Synology Technical
Support for help.
2 If the ALERT LED continuously blinks orange, this indicates there are system errors such as fan failure,
system overheating, or volume degrade. Please sign in to DSM for detailed information.
3 Only for RS2421RP+.
9Chapter 1: Before You Start
Hardware Specication
Item RS2421+/RS2421RP+
Compatible Drive Type 3.5"/2.5" SATA x 12
External Port
• USB 3.2 Gen 1 x 2
•Inniband x 1
LAN Port 1GbE RJ-45 x 4
PCIe Slot Gen3 x8 slot (x4 link) x 1
Size (H x W x D) (mm)
• RS2421+: 88 x 430.5 x 664/
88 x 482 x 696 (with server ears)
• RS2421RP+: 88 x 430.5 x 692/
88 x 482 x 724 (with server ears)
Weight (kg)
• RS2421+: 11.5
• RS2421RP+: 11.9
Supported Client
• Windows 7 onwards
• macOS 10.12 onwards
File System
• Internal: Btrfs, ext4
• External: Btrfs, ext4, ext3, FAT32, NTFS, HFS+, exFAT1
Supported RAID Type
• Basic • JBOD • RAID 0 • RAID 1
• RAID 5 • RAID 6 • RAID 10
• Synology Hybrid RAID (2-Disk Fault Tolerance)
Agency Certication • FCC Class A • CE Class A • BSMI Class A
• EAC • VCCI • CCC • RCM • KC • UL • RoHS Compliant
HDD Hibernation Yes
Scheduled Power On/O Yes
Wake on LAN Yes
Language Localization
Environment Requirement
• Line voltage: 100 V to 240 V AC
• Frequency: 50/60 Hz
•Operating Temperature: 32 to 95˚F (0 to 35˚C)
•Storage Temperature: -5 to 140˚F (-20 to 60˚C)
• Relative Humidity: 5% to 95% RH
Note: Model specications are subject to change without notice. Please refer to www.synology.com for the latest information.
1Support for exFAT can be enabled by purchasing and downloading exFAT Access in Package Center.
10 Chapter 1: Before You Start
Spare Parts
Visit www.synology.com/products/spare_parts if you need to replace system fans, disk trays, or power supply
units
Model Name Picture Description
Disk Tray (Type R7) 3.5"/2.5" Drive Tray With Lock
FAN 60*38_1 System Fan 60*60*38 mm
PSU 500W_4 ATX PSU 500W (for RS2421+)
PSU 350W-RP SET_1 Redundant PSU Set 350W
(for RS2421RP+)
PSU 350W-RP Module_1 Redundant PSU Module 350W
(for RS2421RP+)
Optional Accessories
With Synology accessories, you can customize your Synology NAS to t dierent business environments without
worrying about compatibility and stability. Visit www.synology.com/compatibility for more information.
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