Data Center Drives

SATA is a single-port interface running at up to 6Gb/s, valued for low cost and broad compatibility. SAS runs at 12Gb/s with dual ports for redundancy and failover, plus better support for large arrays. SATA is the choice for cost-efficient capacity, while SAS is ideally suited for performance and availability-critical enterprise storage. 

A SATA (Serial ATA) hard drive uses the standard interface that connects drives to a computer or server, transferring data at up to 6Gb/s. SATA is the most common and cost-effective HDD interface, found everywhere from desktops to capacity-focused data-center drives. It uses a single data path, unlike the dual-port SAS interface. 

Enterprise HDDs deliver the lowest cost per terabyte and the highest capacities, making them ideal for bulk, archival, and capacity-heavy storage. Data-center SSDs are far faster with lower latency but cost more per terabyte, so they suit hot, performance-critical data. Most data centers tier both: SSDs for speed, HDDs for capacity 

RAID combines multiple hard drives into a single logical array to provide redundancy, performance, or both. By mirroring or adding parity, a RAID array can keep running and rebuild data if a drive fails. Data centers rely on RAID with enterprise drives to help protect against downtime and data loss during continuous operation. 

Enterprise data-center HDDs span a wide range, from a few terabytes up to today's highest capacities. WD's current Ultrastar lineup reaches 26TB with CMR (DC HC590) and 32TB with UltraSMR (DC HC690), built on 11-disk helium-sealed designs. Choosing capacity depends on your density, performance, and cost-per-terabyte goals. 

CMR (Conventional Magnetic Recording) writes tracks side by side for consistent performance in any workload. SMR (Shingled Magnetic Recording) overlaps tracks to gain capacity, best for sequential, write-light use. WD's UltraSMR enhances SMR with large-block encoding and advanced error correction to reach the highest capacities, up to 32TB, for sequential and archival storage. 

The standard is NIST Special Publication 800-88, covering Clear, Purge, and Destroy methods. For enterprise HDDs, a cryptographic erase on a self-encrypting drive or an ATA/SAS Secure Erase makes data unrecoverable. When drives leave a controlled environment, physical destruction offers the highest level of assurance. 

Encryption scrambles stored data so only authorized keys can access it. Self-Encrypting Drives (SED) handle this in hardware with no performance penalty, while FIPS 140-2 models meet a U.S. federal security standard. Many Ultrastar drives, including the DC HC500 and HC600 series, offer SED and SED-FIPS versions, with FIPS typically available on SAS models. 

These are successive generations of WD's high-capacity CMR data-center drives, each adding capacity through higher areal density and more platters. The HC550 offers 16-18TB, the HC560 20TB, the HC570 22TB, and the HC580 24TB. All are 3.5-inch, 7200 RPM, helium-sealed drives using ePMR and HelioSeal, with OptiNAND on the newer models from the HC560 onward, and a 2.5-million-hour MTBF and 5-year warranty. 

OptiNAND is WD's flash-enhanced HDD technology that integrates an iNAND embedded flash device on the drive's circuit board. Rather than storing user data, it offloads drive metadata to flash, freeing capacity and increasing areal density. It can also improves write performance and, through ArmorCache, strengthens power-loss protection for data in flight. 

For cold or archival storage, which is sequential and write-light, WD recommends UltraSMR drives. The Ultrastar DC HC680 (28TB) and DC HC690 (32TB) are purpose-built for sequential-write, high-density workloads, delivering the lowest cost and power per terabyte. CMR drives like the HC590 remain better for random, performance-sensitive access.