Storage expansion and accessories Expansion Unit DX525 Expansion Unit DX525
Expansion Unit DX525 Seamless capacity expansion for Synology DiskStation See why Synology drives are ideal
Features Specs
Storage expansion without downtimeEasily add five additional drive bays to your Synology DiskStation. The DX525 supports both 2.5" and 3.5" SATA drives and features plug-and-play setup and hot-swap capability for uninterrupted operation during capacity expansion.
Dedicated local backup solutionThe Synology DX525 provides a dedicated local backup solution for your Synology DiskStation. When configured as a separate volume, it safeguards data on its local disks in case of system failure.
Online volume expansionManaged through the host NAS's DiskStation Manager (DSM), the DX525's additional bays are immediately available upon connection. On-the-fly volume expansion ensures uninterrupted service and storage expansion on the host.

Performance backed by Synology drives

Designed for Synology systems, Synology drives deliver consistent performance and unmatched reliability for your deployments.

HDD
Enterprise Series 3.5" SATA Plus Series 3.5" SATA
SSD
Enterprise Series 2.5" SATA
Hard drives designed for SynologySee how Synology hard drives deliver reliability, consistent performance, and simplified system management through deep hardware-software integration.Watch video
Synology has you coveredThe DX525 is backed by Synology's three-year limited warranty, including technical support and hardware replacement services. Extend your coverage to five years and gain access to premium services that accelerate recovery in the event of a disaster with Extended Warranty Plus. Learn more
Get in touchWhere to buyLearn moreAsk SynologyLearn moreNotes:Please consult our compatibility list before purchasing hard drives. For more details, please refer to this article.The warranty period starts from the date of purchase as stated on your purchase receipt. Visit https://www.synology.com/company/legal/warranty for more information.Up to 5 years of warranty are available as an additional bundle with Extended Warranty Plus or Extended Warranty, both 2-year extended warranty service add-ons available in select regions. Check availability for Extended Warranty or Extended Warranty Plus.
Hardware Specifications
Applied Models
Applied Models
 Supports creating volumes across different units
  • 25 series:DS1825+, DS1525+, DS925+, DS725+
Notes To have better performance, we recommend creating storage volumes physically located within the same NAS or Expansion Unit, rather than creating volumes across your NAS and Expansion Unit.
Storage
Storage
 Drive Bays 5
Drive Type (See all supported drives)
  • 3.5" SATA HDD
  • 2.5" SATA SSD
Hot Swappable Drive*
RAID Management through Synology DSM
Notes Compatible drives are mandatory. Please consult our compatibility list before purchasing hard drives. For more details, please refer to this article.
External Ports
External Ports
 Expansion Port 1
Appearance
Appearance
 Size (Height x Width x Depth) 166 mm x 230 mm x 223 mm
Weight 2.46 kg
Power
Power
 Power Recovery Synchronized with the Synology DiskStation
Power Supply Unit / Adapter 90 W
AC Input Power Voltage 100V to 240V AC
Power Frequency 50/60 Hz, Single Phase
Power Consumption* 35.37 W (Access)
7.0 W (HDD Hibernation)
British Thermal Unit 120.69 BTU/hr (Access)
24.02 BTU/hr (HDD Hibernation)
Notes For more information on how power consumption is measured, refer to this article.
Temperature
Temperature
 Operating Temperature 0°C to 40°C (32°F to 104°F)
Storage Temperature -20°C to 60°C (-5°F to 140°F)
Operating Humidity 8% to 80% RH
Storage Humidity 5% to 95% RH
Others
Others
 System Fan 92 mm x 92 mm x 2 pcs
Noise Level* 20.4 dB(A)
Notes Noise testing was conducted with the Synology system fully installed with Synology SATA HDDs and in an idle state. Two G.R.A.S. Type 40AE microphones are placed at a 1 m distance from the front and rear of the device. Background noise: 16.49-17.51 dB(A); Temperature: 24.25-25.75˚C; Humidity: 58.2-61.8%
Certification
Certification
  • FCC
  • CE
  • BSMI
  • UKCA
  • EAC
  • VCCI
  • RCM
  • KC
  • BIS
Warranty
Warranty
 3-year hardware warranty, extendable to 5 years with EW201 or Extended Warranty Plus
Notes
  • Availability varies by region. Before purchasing, please visit the official web pages of EW201/202 and Extended Warranty Plus for a list of eligible regions.
  • The warranty period starts from the purchase date as stated on your purchase receipt. (Learn more)
Environment & Packaging
Environment
Environment
 RoHS Compliant
Packaging Content
Packaging Content
  • Main Unit X 1
  • Expansion Cable: USB Type-C X1
  • Accessory Pack X 1
  • AC Power Adapter X 1
  • AC Power Cord X 1
Optional Accessories
Optional Accessories
Notes: Model specifications are subject to change without prior notice. The figures are based on Synology internal testing. Each performance test is done individually. No other services or applications are processed at the same time. The actual performance may be lower than lab testing figure due to differences in server configuration, deployment, and the number of active operations. If usage requirements exceed the specifications above, please contact our regional partners for professional advice.