WD Ultrastar HC555 20 TB 3.5 Inch SAS 12Gb/s Enterprise HDD 0B47749

Brand: Western Digital | Category: Enterprise HDDs

SKU: 0B47749 | Part #: 0B47749 | MPN: WUH722020CL5204

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The WD Ultrastar HC555 20 TB 3.5-inch SAS HDD represents a careful balance between capacity and operational efficiency—a balance that matters far more in practice than it does in marketing material. Most JBOD-dense storage deployments hit power constraints long before they run out of rack space, and that's where the HC555 earns its place in serious data centre infrastructure. At just 7.8 W under typical operating load and 5.0 W at idle, this Western Digital enterprise drive delivers the density that storage architects and infrastructure engineers actually need without forcing facility teams to upgrade power distribution or cooling systems. The 20 TB capacity sits at the practical sweet spot for organisations running mixed warm-storage, backup, and archival workloads across GCC and Southeast Asian regions where power costs and cooling capacity remain genuine constraints.

Built on Western Digital's proven Ultrastar HC555 platform, the part number 0B47749 (WUH722020CL5204) ships with helium-sealed construction that keeps platter friction lower than traditional air-filled drives, directly contributing to that power efficiency story. A 512 MB cache buffer and 7200 RPM spindle speed deliver sustained transfer rates up to 269 MB/s—sufficient for sequential restore operations and batch backup processes without becoming a bottleneck in modern SAS 12 Gb/s infrastructure. The dual-port SAS interface is rarely marketed but genuinely valuable in failover scenarios; storage architects appreciate it because it means less complicated cabling when implementing active-active or redundant paths in SAN environments. Western Digital rates the HC555 for 550 TB of annual workload, which translates to roughly 75 GB per day of continuous I/O—realistic for tier-2 storage where you're not hammering the drives but can't afford unexpected downtime either.

Reliability metrics on the Ultrastar HC555 20 TB tell a different story than entry-level or nearline drives. An MTBF of 2,500,000 hours and annualized failure rate of 0.35% mean that when you install a hundred of these drives, you statistically see one failure per three years. That matters when you're calculating RTO/RPO for backup systems or when your storage architect is justifying hardware refresh cycles to finance. The drive includes T10 Protection Information for end-to-end data integrity checking, and a Self-Encrypting Drive option is available for organisations handling regulated data or operating in jurisdictions where encryption at rest is mandatory. Operating temperature range of 5°C to 60°C is wide enough to handle most properly managed data centre environments without thermal throttling concerns. Western Digital stands behind these specifications with substantial field validation; the HC555 line is deployed in thousands of installations worldwide, not just in marketing materials.

If you're a storage administrator evaluating this product, the WD Ultrastar HC555 part number 0B47749 fits cleanly into several real-world scenarios. JBOD backup appliances benefit immediately from the power efficiency when you're building 100-bay or 200-bay configurations. Tier-2 archival systems for organisations migrating cold data off Tier-1 arrays see better cost-per-TB without the performance drag of SMR or conventionally-sealed drives. Even AI labs that need fast local scratch storage for training datasets can justify the SAS interface and power profile because they're not constrained by the same density calculations as hyperscalers. The 3.5-inch form factor, at 650 grams and modest dimensions, slots into standard 3.5-inch server bays and enterprise storage enclosures without requiring custom mounting or re-engineering. Network engineers and storage teams often make this call together because the interface specification and reliability profile affect both sides of the infrastructure.

Omnixon Global stocks the WD Ultrastar HC555 20 TB (0B47749) and maintains relationships with Western Digital regional distribution to serve data centres, systems integrators, and enterprise IT teams across the UAE, GCC, and into Asia. If you're building storage infrastructure that demands both capacity and operational discipline, we'd welcome your RFQ with bill-of-materials details, deployment timelines, and any integration questions. Contact our enterprise storage team to discuss pricing, lead times, and whether the HC555 aligns with your infrastructure roadmap.

Storage Architecture & Deployment Specifications

• 20 TB capacity with 512 MB cache; 7200 RPM spindle and 269 MB/s sustained transfer for mixed workload JBOD systems
• Dual-port SAS 12 Gb/s interface supporting active-active failover and redundant SAN connectivity without topology redesign
• Helium-sealed construction: 7.8 W operating, 5.0 W idle—critical for power-constrained data centre expansion and high-density JBOD appliances
• 2,500,000 hour MTBF and 0.35% AFR with T10 Protection Information and optional Self-Encrypting Drive for regulated environments
• Rated 550 TB/year workload; suitable for Tier-2 backup, archival, warm storage, and non-latency-critical restore operations
• Standard 3.5-inch form factor, 26.1 × 101.6 × 147 mm; integrates directly into existing enterprise storage enclosures and server bays
• 5°C to 60°C operating range; no thermal throttling in standard data centre cooling profiles
• Western Digital Ultrastar brand with field-proven HC555 platform deployed across thousands of production systems globally