Synology DX517 5-Bay DiskStation Expansion Unit

At a Glance

• Adds 5 additional drive bays to compatible Synology DiskStation systems
• Supports compatible 3.5-inch and 2.5-inch SATA drives
• Online storage expansion without interrupting host NAS services
• Hot-swappable drive trays
• Can also be configured as a separate local backup destination
• Managed directly through Synology DSM
• 3-Year Synology Hardware Warranty

Important: The DX517 is an expansion unit, not a standalone NAS. It requires a compatible Synology DiskStation. Storage drives are sold separately.

Short Description

The Synology DX517 is a 5-bay expansion unit designed to add additional storage capacity to compatible Synology DiskStation systems without replacing your existing NAS.

Once connected, the additional drives are managed directly through Synology DSM, giving growing users and businesses a simple way to increase storage or create a dedicated local backup volume.

Why Choose This Synology

Keep Your Existing NAS and Add More Storage

Instead of replacing a compatible DiskStation when it runs out of drive bays, the DX517 adds five more bays to your existing system.

Expand Without Taking Services Offline

Synology supports online volume expansion with compatible host systems, allowing storage capacity to grow while the NAS continues operating.

Use It for Expansion or Backup

The DX517 can expand existing storage or be configured as a separate local volume, making it useful as an additional backup destination.

Easy DSM Management

Once connected to the host DiskStation, drives installed in the DX517 are managed through Synology DSM without requiring separate management software.

Hot-Swappable Drive Bays

Compatible drives can be installed or replaced using the hot-swappable trays without powering down the system.

Best For

• Expanding compatible Synology DiskStation storage
• Businesses whose existing NAS is running out of capacity
• Growing photo and video libraries
• Business backup storage
• Local secondary backup volumes
• Users wanting to extend the life of an existing compatible NAS

Product Description

The Synology DX517 provides a straightforward way to add five additional storage bays to a compatible Synology DiskStation.

It supports compatible 3.5-inch SATA HDDs, 2.5-inch SATA HDDs and 2.5-inch SATA SSDs, giving you flexibility when expanding capacity or building a separate backup volume.

The DX517 connects to the host NAS through eSATA and is managed directly through Synology DiskStation Manager. With compatible host systems, online volume expansion allows additional capacity to be added without interrupting storage services.

Hot-swappable drive trays simplify drive installation and replacement, while the unit can also be configured as a dedicated local backup destination rather than simply extending an existing storage volume.

The DX517 does not operate as a standalone NAS. A compatible Synology DiskStation and compatible storage drives are required.

Key Features

• 5-bay Synology DiskStation expansion unit
• Supports 3.5-inch SATA HDDs
• Supports 2.5-inch SATA HDDs
• Supports 2.5-inch SATA SSDs
• Hot-swappable drive trays
• Online volume expansion
• DSM-based RAID management
• Can be used as a separate local backup volume
• eSATA connection to compatible host NAS
• 3-year Synology hardware warranty

What Do I Need With This Expansion Unit?

Required

• Compatible Synology DiskStation
• Compatible storage drives

The DX517 cannot operate independently.

Before Buying

Confirm:

• Your exact Synology NAS model supports the DX517
• Your chosen drives are compatible
• Your intended storage or volume configuration is supported

Compatible Synology Systems

Synology currently lists the following compatible host systems.

23 Series

DS1823xs+, DS923+, DS723+

22 Series

DS1522+

21 Series

DS1821+, DS1621xs+, DS1621+, DVA3221

20 Series

DS1520+, DS920+, DS720+

19 Series

DS1819+, DS1019+, DVA3219

18 Series

DS1618+, DS918+, DS718+, NVR1218

17 Series

DS1817+, DS1817, DS1517+, DS1517

16 Series

DS916+, DS716+II, DS716+

15 Series

DS1815+, DS1515+, DS1515

The following models support volumes created on a single unit only:

• DS218+
• DS216+II
• DS216+
• NVR216
• DS415+

Compatibility Note: Synology recommends keeping storage volumes physically within the same NAS or expansion unit for better performance rather than spanning a volume across different physical units.

Compatible Storage

Synology lists compatible storage from:

3.5-inch SATA HDD

• HAT5300 Enterprise Series
• HAT3300 Plus Series

2.5-inch SATA SSD

• SAT5200 Enterprise Series

Exact drive compatibility is model-specific. Always check the selected drive against Synology's current DX517 Compatibility List before purchase.

Specifications

What’s in the Box

• Synology DX517 Main Unit × 1
• Accessory Pack × 1
• AC Power Cord × 1
• eSATA Expansion Cable × 1
• Quick Installation Guide × 1

Not Included: Storage drives and host Synology NAS.

Warranty

3-Year Synology Hardware Warranty

Sustainability

• RoHS Compliant