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Silver 3.5-inch enterprise hard drive with SAS connector and label showing 18TB capacity

Western Digital

Western Digital Ultrastar DC HC550 18TB SAS 12Gb/s 7.2K RPM 512MB 3.5" internal hard drive

SKU CH-F71K-A4BGD

Enterprise 18 TB SAS drive with 7200 RPM, 512 MB cache and 2.5 million-hour MTBF for high-capacity storage

  • Total capacity18 TB
  • Interface typeSAS 12Gb/s
  • Form factor3.5 in (8.89 cm)
  • Rotational speed7,200 RPM
  • Cache memory512 MB
  • 18 TB capacity for massive data storage
  • SAS 12 Gb/s interface enables fast transfers
  • 7200 RPM with 512 MB cache speeds access
  • 5 million hours MTBF supports reliability
  • HelioSeal 9-disk design delivers 18 TB density

18 TB SAS Enterprise Hard Drive

The Western Digital Ultrastar DC HC550 is an 18 TB internal hard drive with a SAS 12Gb/s interface, 7200 RPM spindle speed and 512 MB cache. Built on a nine-disk helium-sealed platform, it delivers a sustained transfer rate of 269 MB/s and a 2.5 million hour MTBF rating for continuous operation.

Suited for high-capacity object storage

This drive fits object storage systems that use erasure coding and need maximum density per slot. It is not suited for workloads demanding low-latency random access, single-drive desktop use, or environments that cannot accommodate a 3.5 inch SAS connection.

SAS 12Gb/s interface decides compatibility

The drive requires a backplane or controller that supports 12 Gb/s SAS signalling. Without that interface the drive cannot communicate with the host, making the SAS connection the single specification that determines whether this is the correct part.

How it compares

Measured against everything we stock in 3.5-Inch Internal Desktop HDDs, at today’s prices. Recalculated every night.

Price $441.99
Pricier than about 90% of the 4,938 comparable items (median $107.99).
Total capacity 18 TB
Higher than about 93% of the 2,372 comparable items (median 2 TB).
Price per TB $24.56 per TB
Cheaper than about 90% of the 2,365 comparable items (median $62.21 per TB).

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Specifications

Product
Total capacity18 TB
Performance
Rotational speed7,200 RPM
Storage
Cache memory512 MB
Ports & slots
Interface typeSAS 12Gb/s
Size & build
Form factor3.5 in (8.89 cm)

Questions about this item

Does my server or RAID controller need a SAS 12Gb/s port for this 18TB drive?

Yes, the drive uses a SAS 12Gb/s interface and requires a compatible SAS 12Gb/s HBA, RAID controller or backplane to operate.

Will the 7.2K RPM spindle speed and 512MB cache match the throughput of my existing 7.2K RPM SAS drives?

The drive delivers a sustained transfer rate of 269MB/s and 4.16ms average latency, which is typical for 7.2K RPM enterprise SAS drives.

How can I confirm the HelioSeal platform is healthy after installation?

Check SMART attributes for reallocated sector count and temperature; the drive is rated for 2.5 million hours MTBF under normal enterprise workloads.

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