Comparison results

DS1621xs+ RS422+
Hardware Specs
Hardware Specifications
CPU
CPU Model Intel Xeon D-1527 AMD Ryzen R1600
CPU Quantity 1 1
CPU Architecture 64-bit 64-bit
CPU Frequency 4-core 2.2 (base) / 2.7 (turbo) GHz 2-core 2.6 (base) / 3.1 (turbo) GHz
Hardware Encryption Engine (AES-NI)
Memory
System Memory 8 GB DDR4 ECC SODIMM 2 GB DDR4 ECC
Memory Module Pre-installed 8 GB (8 GB x 1)
Total Memory Slots 2
Maximum Memory Capacity 32 GB (16 GB x 2)
Notes
  • Synology reserves the right to replace memory modules with the same or higher frequency based on supplier's product life cycle status. Rest assured that the compatibility and stability have been strictly verified with the same benchmark to ensure identical performance.
  • Please select Synology memory modules for optimum compatibility and reliability. Synology will not provide complete product warranty or technical support if non-Synology memory modules are used for memory expansion.
  • For more information on the recommended memory configurations, visit here.
Synology reserves the right to replace memory modules with the same or higher frequency based on supplier's product life cycle status. Rest assured that the compatibility and stability have been strictly verified with the same benchmark to ensure identical performance.
Storage
Drive Bays 6 4
Maximum Drive Bays with Expansion Unit 16 (DX517 x 2)
M.2 Drive Slots 2 (NVMe)
Compatible Drive Type* (See all supported drives)
  • 3.5" SATA HDD
  • 2.5" SATA HDD
  • 2.5" SATA SSD
  • M.2 2280 NVMe SSD
  • 3.5" SATA HDD
  • 2.5" SATA SSD
Hot Swappable Drive
Notes "Compatible drive type" indicates drives that have been tested to be compatible with Synology products. This term does not indicate the maximum connection speed of each drive bay. "Compatible drive type" indicates drives that have been tested to be compatible with Synology products. This term does not indicate the maximum connection speed of each drive bay.
External Ports
RJ-45 1GbE LAN Port 2 (with Link Aggregation / Failover support)
RJ-45 1GbE LAN Port* 2 (with Link Aggregation / Failover support)
RJ-45 10GbE LAN Port 1
USB 3.2 Gen 1 Port* 3 1
eSATA Port 2
Notes The USB 3.0 standard was renamed to USB 3.2 Gen 1 by the USB Implementers Forum (USB-IF) in 2019.
  • This device's 1GbE LAN ports have a maximum transmission unit (MTU) size of 1,500 bytes.
  • The USB 3.0 standard was renamed to USB 3.2 Gen 1 by the USB Implementers Forum (USB-IF) in 2019.
PCIe
PCIe Expansion 1 x Gen3 x8 slot (x8 link) 1 x Gen3 x2 network upgrade slot
File System
Internal Drives
  • Btrfs
  • EXT4
  • Btrfs
  • EXT4
External Drives
  • Btrfs
  • EXT4
  • EXT3
  • FAT
  • NTFS
  • HFS+
  • exFAT
  • Btrfs
  • EXT4
  • EXT3
  • FAT
  • NTFS
  • HFS+
  • exFAT
Notes exFAT Access can be installed for free from Package Center in DSM 7.0. In DSM 6.2 or earlier versions, exFAT Access needs to be purchased in Package Center.
Appearance
Form Factor (RU) 1U
Size (Height x Width x Depth) 166 mm x 282 mm x 243 mm 44 mm x 478 mm x 327.5 mm
Weight 5.3 kg 4.38 kg
Rack Installation Support*
  • 4-post 19" rack (Synology Rail Kit - RKM114/RKS-02)
  • 2-post 19" rack (direct mounting)
Notes The rail kit is sold separately
Others
System Fan 92 mm x 92 mm x 2 pcs 40 mm x 40 mm x 3 pcs
Fan Speed Mode
  • Full-Speed Mode
  • Cool Mode
  • Quiet Mode
  • Full-Speed Mode
  • Cool Mode
  • Quiet Mode
Easy Replacement System Fan
Brightness Adjustable Front LED Indicators
Power Recovery
Noise Level* 25.2 dB(A) 28.5 dB(A)
Scheduled Power On / Off
Wake on LAN / WAN
Power Supply Unit / Adapter 250 W 100 W
AC Input Power Voltage 100V to 240V AC 100V to 240V AC
Power Frequency 50/60 Hz, Single Phase 50/60 Hz, Single Phase
Power Consumption* 62.85 W (Access)
34.26 W (HDD Hibernation)
37.93 W (Access)
13.43 W (HDD Hibernation)
British Thermal Unit 214.45 BTU/hr (Access)
116.89 BTU/hr (HDD Hibernation)
129.42 BTU/hr (Access)
45.83 BTU/hr (HDD Hibernation)
Notes
  • Power consumption is measured when it is fully loaded with Western Digital 1TB WD10EFRX hard drive(s).
  • Noise Level Testing Environment: Fully loaded with Seagate 2TB ST2000VN000 hard drive(s) in the idle state. Two G.R.A.S. Type 40AE microphones, each set up 1 meter away from the Synology NAS at the front and rear. Background noise: 16.49-17.51 dB(A); Temperature: 24.25-25.75˚C; Humidity: 58.2-61.8%
For more information on how power consumption is measured, refer to this article.
Temperature
Operating Temperature 0°C to 40°C (32°F to 104°F) 0°C to 35°C (32°F to 95°F)
Storage Temperature -20°C to 60°C (-5°F to 140°F) -20°C to 60°C (-5°F to 140°F)
Relative Humidity 5% to 95% RH 5% to 95% RH
Certification
  • FCC
  • CE
  • BSMI
  • EAC
  • CCC
  • KC
  • VCCI
  • RCM
  • FCC
  • CE
  • BSMI
  • VCCI
  • RCM
  • UKCA
  • EAC
  • CCC
  • KC
Warranty 5 Years 3-year hardware warranty, extendable to 5 years with EW201 or Extended Warranty Plus
Notes The warranty period starts from the purchase date as stated on your purchase receipt. (Learn more)
  • 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 RoHS Compliant RoHS Compliant
Packaging Content
  • Main Unit X 1
  • Accessory Pack X 1
  • AC Power Cord X 1
  • RJ-45 LAN Cable X 2
  • Quick Installation Guide X 1
  • Main Unit X 1
  • Accessory Pack X 1
  • AC Power Cord X 1
  • Quick Installation Guide X 1
Optional Accessories
Notes All memory modules will operate at the maximum frequency specified by the CPU manufacturer. Certain items may not be available in your location. Please contact your local distributors for more information.
Software Specs
DSM Specifications
Storage Management
Maximum Single Volume Size*
  • 200 TB (32 GB memory required)
  • 108 TB
108 TB
Maximum Internal Volume Number 256 64
SSD Read / Write Cache (White Paper)
SSD TRIM
RAID Group
Supported RAID Type
  • RAID F1
  • Basic
  • JBOD
  • RAID 0
  • RAID 1
  • RAID 5
  • RAID 6
  • RAID 10
  • Synology Hybrid RAID
  • Basic
  • JBOD
  • RAID 0
  • RAID 1
  • RAID 5
  • RAID 6
  • RAID 10
RAID Migration
  • Basic to RAID 1
  • Basic to RAID 5
  • RAID 1 to RAID 5
  • RAID 5 to RAID 6
  • Basic to RAID 1
  • Basic to RAID 5
  • RAID 1 to RAID 5
  • RAID 5 to RAID 6
Volume Expansion with Larger HDDs
  • RAID F1
  • RAID 1
  • RAID 5
  • RAID 6
  • RAID 10
  • Synology Hybrid RAID
  • RAID 1
  • RAID 5
  • RAID 6
  • RAID 10
Volume Expansion by Adding a HDD
  • RAID F1
  • JBOD
  • RAID 5
  • RAID 6
  • Synology Hybrid RAID
  • JBOD
  • RAID 5
Global Hot Spare Supported RAID Type
  • RAID F1
  • RAID 1
  • RAID 5
  • RAID 6
  • RAID 10
  • Synology Hybrid RAID
  • RAID 1
  • RAID 5
Notes
  • Usable capacity for each volume will be lower than the maximum volume size and is dependent on the filesystem and the amount of system metadata stored.
  • Each internal volume (may consist of multiple drives) is expandable up to 108 TB (with memory less than 32 GB) or 200 TB (with memory equal to or greater than 32 GB).
  • Usable capacity for each volume will be lower than the maximum volume size and is dependent on the filesystem and the amount of system metadata stored.
  • Actual maximum storage pool and volume sizes vary depending on drives used, the number of drive bays available, and the RAID configuration.
File Services
File Protocol SMB/AFP/NFS/FTP/WebDAV SMB/AFP/NFS/FTP/WebDAV
Maximum Concurrent SMB/AFP/FTP Connections 2,000 500
Maximum Concurrent SMB/AFP/FTP Connections (with RAM expansion) 8,000
Windows Access Control List (ACL) Integration
NFS Kerberos Authentication
Notes
  • Regarding data concerning tests with RAM expansion, all memory slots are installed with the maximum capacity of supported RAM.
  • During testing, the maximum number of SSDs supported by this model is installed in a RAID 5 configuration.
  • The testing standard was based on the maximum number of concurrent connections supported by this model. During the testing, 25% of the connections were used to transfer files concurrently. The transfer process guaranteed that the connections were not interrupted; the minimum transfer speed was not guaranteed.
The testing standard was based on the maximum number of concurrent connections supported by this model. During the testing, 25% of the connections were used to transfer files concurrently. The transfer process guaranteed that the connections were not interrupted; the minimum transfer speed was not guaranteed.
Account & Shared Folder
Maximum Local User Accounts 16,000 2,048
Maximum Local Groups 512 256
Maximum Shared Folder 512 512
Maximum Shared Folder Sync Tasks 32 8
Hybrid Share
Hybrid Share Folder Number 15 10
Notes For more supported details, please check this article. For more supported details, please check this article.
High Availability
Synology High Availability
Log Center
Syslog Events per Second 1,500 800
Virtualization
VMware vSphere with VAAI
Windows Server 2016
Windows Server 2019
Citrix Ready
OpenStack
General Specifications
Networking Protocols SMB1 (CIFS), SMB2, SMB3, NFSv3, NFSv4, NFSv4.1, NFS Kerberized sessions, iSCSI, Fibre Channel, HTTP, HTTPs, FTP, SNMP, LDAP, CalDAV SMB1 (CIFS), SMB2, SMB3, NFSv3, NFSv4, NFSv4.1, NFS Kerberized sessions, iSCSI, HTTP, HTTPs, FTP, SNMP, LDAP, CalDAV
Supported Browsers
  • Google Chrome
  • Firefox
  • Microsoft Edge
  • Safari
  • Google Chrome
  • Firefox
  • Microsoft Edge
  • Safari
Supported Language English, Deutsch, Français, Italiano, Español, Dansk, Norsk, Svenska, Nederlands, Русский, Polski, Magyar, Português do Brasil, Português Europeu, Türkçe, Český, ภาษาไทย, 日本語, 한국어, 繁體中文, 简体中文 English, Deutsch, Français, Italiano, Español, Dansk, Norsk, Svenska, Nederlands, Русский, Polski, Magyar, Português do Brasil, Português Europeu, Türkçe, Český, ภาษาไทย, 日本語, 한국어, 繁體中文, 简体中文
Notes For an updated list of supported browser versions, check the DSM Technical Specifications. For an updated list of supported browser versions, check the DSM Technical Specifications.
Add-on Packages view the complete package list
Antivirus by McAfee (Trial)
Central Management System
Synology Chat
Maximum Users 4,000
Maximum Number of Concurrent Users 400 100
Notes When applicable, tested systems are configured with maximum memory and set to allow the maximum number of connections.
  • Measured with simulated users, each with an average record of 20,000 messages, emojis, or stickers. The required server response time is below ten seconds.
  • When applicable, tested systems are configured with maximum memory and set to allow the maximum number of connections.
Document Viewer
Download Station
Maximum Concurrent Download Tasks 80 80
SAN Manager
Maximum iSCSI Target Number 256 128
Maximum LUN 512 256
LUN Clone/Snapshot, Windows ODX
Notes iSCSI Manager has been renamed to SAN Manager in DSM 7.0.
Synology MailPlus / MailPlus Server
Free Email Accounts 5 (Licenses required for additional accounts)
Maximum Number of Concurrent Users 450
Maximum Server Performance 3,363,000 emails per day, approx. 102GB
Notes
  • Models with more than 4 bays were installed with two SSDs for SSD cache.
  • For tested models with expandable memory, the maximum amount of RAM was installed.
  • The performance of the mail system will slightly decrease in high-availability mode due to data synchronization between the two servers.
  • Functions that were enabled in all of the tests above: anti-spam, anti-virus, DNSBL, greylist, content scan, full-text search (English only).
Media Server
DLNA Compliance
Synology Photos
Facial Recognition
Snapshot Replication
Maximum Snapshots per Shared Folder 1,024 1,024
Maximum of System Snapshots 65,536 65,536
Surveillance Station
Maximum IP cam (Licenses required) 75 (including 2 Free License) (see all supported IP cameras) 40 (including 2 Free License) (see all supported IP cameras)
Total FPS (H.264) 2250 FPS @ 720p (1280x720)
1050 FPS @ 1080p (1920x1080)
600 FPS @ 3M (2048x1536)
400 FPS @ 5M (2591x1944)
280 FPS @ 4K (3840x2160)
1200 FPS @ 720p (1280x720)
800 FPS @ 1080p (1920x1080)
350 FPS @ 3M (2048x1536)
280 FPS @ 5M (2591x1944)
170 FPS @ 4K (3840x2160)
Total FPS (H.265) 2250 FPS @ 720p (1280x720)
2250 FPS @ 1080p (1920x1080)
1125 FPS @ 3M (2048x1536)
700 FPS @ 5M (2591x1944)
490 FPS @ 4K (3840x2160)
1200 FPS @ 720p (1280x720)
1200 FPS @ 1080p (1920x1080)
600 FPS @ 3M (2048x1536)
480 FPS @ 5M (2591x1944)
200 FPS @ 4K (3840x2160)
Notes
  • Maximum IP cameras and FPS figures are tested with the device fully populated with drives and under a continuous recording setup.
  • Actual system capabilities may differ depending on system configuration, drive performance, number of features enabled, and if additional workloads are present.
  • Maximum IP cameras and FPS figures are tested with the device fully populated with drives and under a continuous recording setup.
  • Actual system capabilities may differ depending on system configuration, drive performance, number of features enabled, and if additional workloads are present.
Synology Drive
Recommended Number of Concurrent Sync Clients 900 (the number of connections that can be maintained when the recommended number of hosted files was reached) 350 (the number of connections that can be maintained when the recommended number of hosted files was reached)
Recommended Number of Hosted Files 50,000,000 (applies to files indexed or hosted by Synology Drive. For file access through other standard protocols, refer to the File Services section above) 5,000,000 (applies to files indexed or hosted by Synology Drive. For file access through other standard protocols, refer to the File Services section above)
Notes
  • Exceeding the recommended numbers above will not block application operations, but may result in longer response time.
  • Utilizing SSD cache can significantly improve performance.
  • For tested models with expandable memory, the maximum amount of RAM was installed.
  • Btrfs file system and non-encrypted shared folders were used during the aforementioned testing.
  • Exceeding the recommended numbers above will not block application operations, but may result in longer response time.
  • Utilizing SSD cache can significantly improve performance.
  • Btrfs file system and non-encrypted shared folders were used during the aforementioned testing.
Synology Office
Maximum Users 2,900 200
Notes
  • Multiple files were opened for testing and each file was edited by 30 users simultaneously.
  • For tested models with expandable memory, the maximum amount of RAM was installed.
  • Client performance may affect maximum simultaneous editing users. Client PCs used for testing: Intel Core i3-3220 / 8GB RAM
  • Multiple files were opened for testing and each file was edited by 30 users simultaneously.
  • Client performance may affect maximum simultaneous editing users. Client PCs used for testing: Intel Core i3-3220 / 8GB RAM
Video Station
Virtual Machine Manager
Recommended Virtual Machine Instances 8 (Learn more)
Recommended Virtual DSM Number (Licenses required) 8 (including 1 Free License)
Notes The specifications vary depending on system configuration and memory size.
VPN Server
Maximum Connections 60 40
Hardware Specs
Hardware Specifications
CPU
CPU Model
DS1621xs+ Intel Xeon D-1527
RS422+ AMD Ryzen R1600
CPU Quantity
DS1621xs+ 1
RS422+ 1
CPU Architecture
DS1621xs+ 64-bit
RS422+ 64-bit
CPU Frequency
DS1621xs+ 4-core 2.2 (base) / 2.7 (turbo) GHz
RS422+ 2-core 2.6 (base) / 3.1 (turbo) GHz
Hardware Encryption Engine (AES-NI)
DS1621xs+
RS422+
Memory
System Memory
DS1621xs+ 8 GB DDR4 ECC SODIMM
RS422+ 2 GB DDR4 ECC
Memory Module Pre-installed
DS1621xs+ 8 GB (8 GB x 1)
RS422+
Total Memory Slots
DS1621xs+ 2
RS422+
Maximum Memory Capacity
DS1621xs+ 32 GB (16 GB x 2)
RS422+
Notes
DS1621xs+
  • Synology reserves the right to replace memory modules with the same or higher frequency based on supplier's product life cycle status. Rest assured that the compatibility and stability have been strictly verified with the same benchmark to ensure identical performance.
  • Please select Synology memory modules for optimum compatibility and reliability. Synology will not provide complete product warranty or technical support if non-Synology memory modules are used for memory expansion.
  • For more information on the recommended memory configurations, visit here.
RS422+ Synology reserves the right to replace memory modules with the same or higher frequency based on supplier's product life cycle status. Rest assured that the compatibility and stability have been strictly verified with the same benchmark to ensure identical performance.
Storage
Drive Bays
DS1621xs+ 6
RS422+ 4
Maximum Drive Bays with Expansion Unit
DS1621xs+ 16 (DX517 x 2)
RS422+
M.2 Drive Slots
DS1621xs+ 2 (NVMe)
RS422+
Compatible Drive Type* (See all supported drives)
DS1621xs+
  • 3.5" SATA HDD
  • 2.5" SATA HDD
  • 2.5" SATA SSD
  • M.2 2280 NVMe SSD
RS422+
  • 3.5" SATA HDD
  • 2.5" SATA SSD
Hot Swappable Drive
DS1621xs+
RS422+
Notes
DS1621xs+ "Compatible drive type" indicates drives that have been tested to be compatible with Synology products. This term does not indicate the maximum connection speed of each drive bay.
RS422+ "Compatible drive type" indicates drives that have been tested to be compatible with Synology products. This term does not indicate the maximum connection speed of each drive bay.
External Ports
RJ-45 1GbE LAN Port
DS1621xs+ 2 (with Link Aggregation / Failover support)
RS422+
RJ-45 1GbE LAN Port*
DS1621xs+
RS422+ 2 (with Link Aggregation / Failover support)
RJ-45 10GbE LAN Port
DS1621xs+ 1
RS422+
USB 3.2 Gen 1 Port*
DS1621xs+ 3
RS422+ 1
eSATA Port
DS1621xs+ 2
RS422+
Notes
DS1621xs+ The USB 3.0 standard was renamed to USB 3.2 Gen 1 by the USB Implementers Forum (USB-IF) in 2019.
RS422+
  • This device's 1GbE LAN ports have a maximum transmission unit (MTU) size of 1,500 bytes.
  • The USB 3.0 standard was renamed to USB 3.2 Gen 1 by the USB Implementers Forum (USB-IF) in 2019.
PCIe
PCIe Expansion
DS1621xs+ 1 x Gen3 x8 slot (x8 link)
RS422+ 1 x Gen3 x2 network upgrade slot
File System
Internal Drives
DS1621xs+
  • Btrfs
  • EXT4
RS422+
  • Btrfs
  • EXT4
External Drives
DS1621xs+
  • Btrfs
  • EXT4
  • EXT3
  • FAT
  • NTFS
  • HFS+
  • exFAT
RS422+
  • Btrfs
  • EXT4
  • EXT3
  • FAT
  • NTFS
  • HFS+
  • exFAT
Notes
DS1621xs+ exFAT Access can be installed for free from Package Center in DSM 7.0. In DSM 6.2 or earlier versions, exFAT Access needs to be purchased in Package Center.
RS422+
Appearance
Form Factor (RU)
DS1621xs+
RS422+ 1U
Size (Height x Width x Depth)
DS1621xs+ 166 mm x 282 mm x 243 mm
RS422+ 44 mm x 478 mm x 327.5 mm
Weight
DS1621xs+ 5.3 kg
RS422+ 4.38 kg
Rack Installation Support*
DS1621xs+
RS422+
  • 4-post 19" rack (Synology Rail Kit - RKM114/RKS-02)
  • 2-post 19" rack (direct mounting)
Notes
DS1621xs+
RS422+ The rail kit is sold separately
Others
System Fan
DS1621xs+ 92 mm x 92 mm x 2 pcs
RS422+ 40 mm x 40 mm x 3 pcs
Fan Speed Mode
DS1621xs+
  • Full-Speed Mode
  • Cool Mode
  • Quiet Mode
RS422+
  • Full-Speed Mode
  • Cool Mode
  • Quiet Mode
Easy Replacement System Fan
DS1621xs+
RS422+
Brightness Adjustable Front LED Indicators
DS1621xs+
RS422+
Power Recovery
DS1621xs+
RS422+
Noise Level*
DS1621xs+ 25.2 dB(A)
RS422+ 28.5 dB(A)
Scheduled Power On / Off
DS1621xs+
RS422+
Wake on LAN / WAN
DS1621xs+
RS422+
Power Supply Unit / Adapter
DS1621xs+ 250 W
RS422+ 100 W
AC Input Power Voltage
DS1621xs+ 100V to 240V AC
RS422+ 100V to 240V AC
Power Frequency
DS1621xs+ 50/60 Hz, Single Phase
RS422+ 50/60 Hz, Single Phase
Power Consumption*
DS1621xs+ 62.85 W (Access)
34.26 W (HDD Hibernation)
RS422+ 37.93 W (Access)
13.43 W (HDD Hibernation)
British Thermal Unit
DS1621xs+ 214.45 BTU/hr (Access)
116.89 BTU/hr (HDD Hibernation)
RS422+ 129.42 BTU/hr (Access)
45.83 BTU/hr (HDD Hibernation)
Notes
DS1621xs+
  • Power consumption is measured when it is fully loaded with Western Digital 1TB WD10EFRX hard drive(s).
  • Noise Level Testing Environment: Fully loaded with Seagate 2TB ST2000VN000 hard drive(s) in the idle state. Two G.R.A.S. Type 40AE microphones, each set up 1 meter away from the Synology NAS at the front and rear. Background noise: 16.49-17.51 dB(A); Temperature: 24.25-25.75˚C; Humidity: 58.2-61.8%
RS422+ For more information on how power consumption is measured, refer to this article.
Temperature
Operating Temperature
DS1621xs+ 0°C to 40°C (32°F to 104°F)
RS422+ 0°C to 35°C (32°F to 95°F)
Storage Temperature
DS1621xs+ -20°C to 60°C (-5°F to 140°F)
RS422+ -20°C to 60°C (-5°F to 140°F)
Relative Humidity
DS1621xs+ 5% to 95% RH
RS422+ 5% to 95% RH
Certification
DS1621xs+
  • FCC
  • CE
  • BSMI
  • EAC
  • CCC
  • KC
  • VCCI
  • RCM
RS422+
  • FCC
  • CE
  • BSMI
  • VCCI
  • RCM
  • UKCA
  • EAC
  • CCC
  • KC
Warranty
DS1621xs+ 5 Years
RS422+ 3-year hardware warranty, extendable to 5 years with EW201 or Extended Warranty Plus
Notes
DS1621xs+ The warranty period starts from the purchase date as stated on your purchase receipt. (Learn more)
RS422+
  • 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
DS1621xs+ RoHS Compliant
RS422+ RoHS Compliant
Packaging Content
DS1621xs+
  • Main Unit X 1
  • Accessory Pack X 1
  • AC Power Cord X 1
  • RJ-45 LAN Cable X 2
  • Quick Installation Guide X 1
RS422+
  • Main Unit X 1
  • Accessory Pack X 1
  • AC Power Cord X 1
  • Quick Installation Guide X 1
Optional Accessories
DS1621xs+
RS422+
Notes
DS1621xs+ All memory modules will operate at the maximum frequency specified by the CPU manufacturer.
RS422+ Certain items may not be available in your location. Please contact your local distributors for more information.
Software Specs
DSM Specifications
Maximum Single Volume Size*
DS1621xs+
  • 200 TB (32 GB memory required)
  • 108 TB
RS422+ 108 TB
Maximum Internal Volume Number
DS1621xs+ 256
RS422+ 64
SSD Read / Write Cache (White Paper)
DS1621xs+
RS422+
SSD TRIM
DS1621xs+
RS422+
RAID Group
DS1621xs+
RS422+
Supported RAID Type
DS1621xs+
  • RAID F1
  • Basic
  • JBOD
  • RAID 0
  • RAID 1
  • RAID 5
  • RAID 6
  • RAID 10
RS422+
  • Synology Hybrid RAID
  • Basic
  • JBOD
  • RAID 0
  • RAID 1
  • RAID 5
  • RAID 6
  • RAID 10
RAID Migration
DS1621xs+
  • Basic to RAID 1
  • Basic to RAID 5
  • RAID 1 to RAID 5
  • RAID 5 to RAID 6
RS422+
  • Basic to RAID 1
  • Basic to RAID 5
  • RAID 1 to RAID 5
  • RAID 5 to RAID 6
Volume Expansion with Larger HDDs
DS1621xs+
  • RAID F1
  • RAID 1
  • RAID 5
  • RAID 6
  • RAID 10
RS422+
  • Synology Hybrid RAID
  • RAID 1
  • RAID 5
  • RAID 6
  • RAID 10
Volume Expansion by Adding a HDD
DS1621xs+
  • RAID F1
  • JBOD
  • RAID 5
  • RAID 6
RS422+
  • Synology Hybrid RAID
  • JBOD
  • RAID 5
Global Hot Spare Supported RAID Type
DS1621xs+
  • RAID F1
  • RAID 1
  • RAID 5
  • RAID 6
  • RAID 10
RS422+
  • Synology Hybrid RAID
  • RAID 1
  • RAID 5
Notes
DS1621xs+
  • Usable capacity for each volume will be lower than the maximum volume size and is dependent on the filesystem and the amount of system metadata stored.
  • Each internal volume (may consist of multiple drives) is expandable up to 108 TB (with memory less than 32 GB) or 200 TB (with memory equal to or greater than 32 GB).
RS422+
  • Usable capacity for each volume will be lower than the maximum volume size and is dependent on the filesystem and the amount of system metadata stored.
  • Actual maximum storage pool and volume sizes vary depending on drives used, the number of drive bays available, and the RAID configuration.
File Protocol
DS1621xs+ SMB/AFP/NFS/FTP/WebDAV
RS422+ SMB/AFP/NFS/FTP/WebDAV
Maximum Concurrent SMB/AFP/FTP Connections
DS1621xs+ 2,000
RS422+ 500
Maximum Concurrent SMB/AFP/FTP Connections (with RAM expansion)
DS1621xs+ 8,000
RS422+
Windows Access Control List (ACL) Integration
DS1621xs+
RS422+
NFS Kerberos Authentication
DS1621xs+
RS422+
Notes
DS1621xs+
  • Regarding data concerning tests with RAM expansion, all memory slots are installed with the maximum capacity of supported RAM.
  • During testing, the maximum number of SSDs supported by this model is installed in a RAID 5 configuration.
  • The testing standard was based on the maximum number of concurrent connections supported by this model. During the testing, 25% of the connections were used to transfer files concurrently. The transfer process guaranteed that the connections were not interrupted; the minimum transfer speed was not guaranteed.
RS422+ The testing standard was based on the maximum number of concurrent connections supported by this model. During the testing, 25% of the connections were used to transfer files concurrently. The transfer process guaranteed that the connections were not interrupted; the minimum transfer speed was not guaranteed.
Maximum Local User Accounts
DS1621xs+ 16,000
RS422+ 2,048
Maximum Local Groups
DS1621xs+ 512
RS422+ 256
Maximum Shared Folder
DS1621xs+ 512
RS422+ 512
Maximum Shared Folder Sync Tasks
DS1621xs+ 32
RS422+ 8
Hybrid Share Folder Number
DS1621xs+ 15
RS422+ 10
Notes
DS1621xs+ For more supported details, please check this article.
RS422+ For more supported details, please check this article.
Synology High Availability
DS1621xs+
RS422+
DS1621xs+
RS422+
Syslog Events per Second
DS1621xs+ 1,500
RS422+ 800
Virtualization
VMware vSphere with VAAI
DS1621xs+
RS422+
Windows Server 2016
DS1621xs+
RS422+
Windows Server 2019
DS1621xs+
RS422+
Citrix Ready
DS1621xs+
RS422+
OpenStack
DS1621xs+
RS422+
Networking Protocols
DS1621xs+ SMB1 (CIFS), SMB2, SMB3, NFSv3, NFSv4, NFSv4.1, NFS Kerberized sessions, iSCSI, Fibre Channel, HTTP, HTTPs, FTP, SNMP, LDAP, CalDAV
RS422+ SMB1 (CIFS), SMB2, SMB3, NFSv3, NFSv4, NFSv4.1, NFS Kerberized sessions, iSCSI, HTTP, HTTPs, FTP, SNMP, LDAP, CalDAV
Supported Browsers
DS1621xs+
  • Google Chrome
  • Firefox
  • Microsoft Edge
  • Safari
RS422+
  • Google Chrome
  • Firefox
  • Microsoft Edge
  • Safari
Supported Language
DS1621xs+ English, Deutsch, Français, Italiano, Español, Dansk, Norsk, Svenska, Nederlands, Русский, Polski, Magyar, Português do Brasil, Português Europeu, Türkçe, Český, ภาษาไทย, 日本語, 한국어, 繁體中文, 简体中文
RS422+ English, Deutsch, Français, Italiano, Español, Dansk, Norsk, Svenska, Nederlands, Русский, Polski, Magyar, Português do Brasil, Português Europeu, Türkçe, Český, ภาษาไทย, 日本語, 한국어, 繁體中文, 简体中文
Notes
DS1621xs+ For an updated list of supported browser versions, check the DSM Technical Specifications.
RS422+ For an updated list of supported browser versions, check the DSM Technical Specifications.
Antivirus by McAfee (Trial)
DS1621xs+
RS422+
DS1621xs+
RS422+
DS1621xs+
RS422+
Maximum Users
DS1621xs+ 4,000
RS422+
Maximum Number of Concurrent Users
DS1621xs+ 400
RS422+ 100
Notes
DS1621xs+ When applicable, tested systems are configured with maximum memory and set to allow the maximum number of connections.
RS422+
  • Measured with simulated users, each with an average record of 20,000 messages, emojis, or stickers. The required server response time is below ten seconds.
  • When applicable, tested systems are configured with maximum memory and set to allow the maximum number of connections.
Document Viewer
DS1621xs+
RS422+
Download Station
DS1621xs+
RS422+
Maximum Concurrent Download Tasks
DS1621xs+ 80
RS422+ 80
DS1621xs+
RS422+
Maximum iSCSI Target Number
DS1621xs+ 256
RS422+ 128
Maximum LUN
DS1621xs+ 512
RS422+ 256
LUN Clone/Snapshot, Windows ODX
DS1621xs+
RS422+
Notes
DS1621xs+ iSCSI Manager has been renamed to SAN Manager in DSM 7.0.
RS422+
DS1621xs+
RS422+
Free Email Accounts
Maximum Number of Concurrent Users
DS1621xs+ 450
RS422+
Maximum Server Performance
DS1621xs+ 3,363,000 emails per day, approx. 102GB
RS422+
Notes
DS1621xs+
  • Models with more than 4 bays were installed with two SSDs for SSD cache.
  • For tested models with expandable memory, the maximum amount of RAM was installed.
  • The performance of the mail system will slightly decrease in high-availability mode due to data synchronization between the two servers.
  • Functions that were enabled in all of the tests above: anti-spam, anti-virus, DNSBL, greylist, content scan, full-text search (English only).
RS422+
DS1621xs+
RS422+
DLNA Compliance
DS1621xs+
RS422+
DS1621xs+
RS422+
Facial Recognition
DS1621xs+
RS422+
DS1621xs+
RS422+
Maximum Snapshots per Shared Folder
DS1621xs+ 1,024
RS422+ 1,024
Maximum of System Snapshots
DS1621xs+ 65,536
RS422+ 65,536
DS1621xs+
RS422+
Maximum IP cam (Licenses required)
DS1621xs+ 75 (including 2 Free License) (see all supported IP cameras)
RS422+ 40 (including 2 Free License) (see all supported IP cameras)
Total FPS (H.264)
DS1621xs+ 2250 FPS @ 720p (1280x720)
1050 FPS @ 1080p (1920x1080)
600 FPS @ 3M (2048x1536)
400 FPS @ 5M (2591x1944)
280 FPS @ 4K (3840x2160)
RS422+ 1200 FPS @ 720p (1280x720)
800 FPS @ 1080p (1920x1080)
350 FPS @ 3M (2048x1536)
280 FPS @ 5M (2591x1944)
170 FPS @ 4K (3840x2160)
Total FPS (H.265)
DS1621xs+ 2250 FPS @ 720p (1280x720)
2250 FPS @ 1080p (1920x1080)
1125 FPS @ 3M (2048x1536)
700 FPS @ 5M (2591x1944)
490 FPS @ 4K (3840x2160)
RS422+ 1200 FPS @ 720p (1280x720)
1200 FPS @ 1080p (1920x1080)
600 FPS @ 3M (2048x1536)
480 FPS @ 5M (2591x1944)
200 FPS @ 4K (3840x2160)
Notes
DS1621xs+
  • Maximum IP cameras and FPS figures are tested with the device fully populated with drives and under a continuous recording setup.
  • Actual system capabilities may differ depending on system configuration, drive performance, number of features enabled, and if additional workloads are present.
RS422+
  • Maximum IP cameras and FPS figures are tested with the device fully populated with drives and under a continuous recording setup.
  • Actual system capabilities may differ depending on system configuration, drive performance, number of features enabled, and if additional workloads are present.
DS1621xs+
RS422+
Recommended Number of Concurrent Sync Clients
DS1621xs+ 900 (the number of connections that can be maintained when the recommended number of hosted files was reached)
RS422+ 350 (the number of connections that can be maintained when the recommended number of hosted files was reached)
Recommended Number of Hosted Files
DS1621xs+ 50,000,000 (applies to files indexed or hosted by Synology Drive. For file access through other standard protocols, refer to the File Services section above)
RS422+ 5,000,000 (applies to files indexed or hosted by Synology Drive. For file access through other standard protocols, refer to the File Services section above)
Notes
DS1621xs+
  • Exceeding the recommended numbers above will not block application operations, but may result in longer response time.
  • Utilizing SSD cache can significantly improve performance.
  • For tested models with expandable memory, the maximum amount of RAM was installed.
  • Btrfs file system and non-encrypted shared folders were used during the aforementioned testing.
RS422+
  • Exceeding the recommended numbers above will not block application operations, but may result in longer response time.
  • Utilizing SSD cache can significantly improve performance.
  • Btrfs file system and non-encrypted shared folders were used during the aforementioned testing.
DS1621xs+
RS422+
Maximum Users
DS1621xs+ 2,900
RS422+ 200
Notes
DS1621xs+
  • Multiple files were opened for testing and each file was edited by 30 users simultaneously.
  • For tested models with expandable memory, the maximum amount of RAM was installed.
  • Client performance may affect maximum simultaneous editing users. Client PCs used for testing: Intel Core i3-3220 / 8GB RAM
RS422+
  • Multiple files were opened for testing and each file was edited by 30 users simultaneously.
  • Client performance may affect maximum simultaneous editing users. Client PCs used for testing: Intel Core i3-3220 / 8GB RAM
DS1621xs+
RS422+
DS1621xs+
RS422+
Recommended Virtual Machine Instances
DS1621xs+ 8 (Learn more)
RS422+
Recommended Virtual DSM Number (Licenses required)
DS1621xs+ 8 (including 1 Free License)
RS422+
Notes
DS1621xs+ The specifications vary depending on system configuration and memory size.
RS422+
DS1621xs+
RS422+
Maximum Connections
DS1621xs+ 60
RS422+ 40