Protecting your company's assets
The 16-bay RS4021xs+ provides powerful data protection and lightning-fast operation with 4K random read IOPS over 234K and sequential read speed of 6258MB/s1. Based on the octa-core processor, ECC memory, advanced snapshot technology and built-in 10 GbE network connection, the RS4021xs+ can serve large multi-user environments while handling high data traffic tasks.

The RS4021xs+ ensures the continuous availability of vital data, so businesses can deliver the best possible results even in the event of a disaster.

Redundant power supply
The two power supplies provide protection against power supply failure and accidental unplugging of the power cord, while hot-swappable fans can be replaced without shutting down the system.

Maximum availability of services
By pairing two identically designed units, Synology High Availability (SHA) creates an active-passive cluster with failover in minutes. More information

A new generation of file system
The Btrfs file system uses advanced storage technologies and optimized snapshots to prevent data loss and reduce maintenance costs.

Double the bandwidth
You can more than double your network bandwidth in minutes with Synology's 10 GbE network adapters.

SSD cache
You can increase read/write IOPS up to 16 times by enabling SSD cache, using Synology M.2 NVMe adapter cards and SNV3500 type SSD units, or installing one or more 2.5-inch SAT5200 SSD units.

Storage for virtualization
Synology iSCSI storage supports popular virtualization solutions, so you can work efficiently with this easy-to-use interface. VMware vSphere 6.5 and VAAI integration help offload storage operations. The Windows Offloaded Data Transfer (ODX) function speeds up data transfer. With OpenStack Cinder support, you can turn your Synology NAS device into a block-based storage component. In addition, Synology Storage Console enables even more simplified storage provisioning and management settings in VMware and Windows environments.