The Synology SA3400D is an enterprise-grade 12-bay 2U rackmount high-availability NAS featuring dual independent controllers in active-passive configuration for automatic minute-level failover and maximum uptime. Each controller features a 2.1 GHz Intel Xeon D-1541 8-core processor with 8GB DDR4 ECC RAM (32GB total, expandable to 128GB), ensuring memory and cache protection with full data synchronization between nodes. Delivers exceptional performance with sequential reads over 3500 MB/s, sequential writes over 2900 MB/s, and 4K random reads over 340,000 IOPS for demanding NAS and SAN applications. Features dual 10 Gigabit Ethernet and four Gigabit Ethernet ports with failover support, dual redundant 500W power supplies, and hot-swappable components to eliminate single points of failure. Supports 3.5" SAS drives and 2.5" SAS SSDs with flexible RAID configurations (0, 1, 5, 6, 10, Basic, F1, JBOD) and AES-NI encryption. Expandable to 36 drive bays using two RXD1219sas expansion units, with two PCIe Gen3 x8 slots for network upgrades and SSD cache. Running on DiskStation Manager (DSM) with Snapshot Replication (RPO as low as 5 minutes), Active Backup Suite, and Hyper Backup. Certified for VMware vSphere, Citrix XenServer, and OpenStack with VAAI/ODX support. Ideal for mission-critical applications requiring zero downtime including file sharing, block storage, and virtualization. Backed by a 5-year limited warranty with Synology Replacement Service (SRS) offering next-business-day advance replacement in selected regions.