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The Drive That Doubles Areal Density with Lasers — And Proves the Physics Works at Scale

Every hard drive in production today uses PMR (Perpendicular Magnetic Recording) or its derivatives. Seagate’s Exos 2X18 uses something fundamentally different: HAMR (Heat-Assisted Magnetic Recording), where a tiny laser heats each magnetic bit to the Curie point before writing, enabling denser bit packing on the platter. HAMR is not a marketing name — it is a physics breakthrough that Seagate has shipped in volume since 2023. The Exos 2X18 is the 18TB production drive that proves the technology works in enterprise environments: 2.5 million hours MTBF, 550 TB/año de carga de trabajo, CMR recording, and a 5-year warranty.

Especificaciones técnicas

Parámetro	Especificación
Capacidad	18tuberculosis (dual actuator: 2x 9TB logical volumes)
Factor de forma	3.5-pulgada LFF
Interfaz	SAS de 12 Gb/s (dual-port) or SATA 6Gb/s (single-port)
Velocidad rotacional	7,200 RPM
Tecnología de grabación	HAMR (Heat-Assisted Magnetic Recording), CMR organization
Actuators	2x independent actuators (MACH.2 dual-actuator technology) — each actuator services half the drive (9TB per actuator)
Búfer de caché	512 MEGABYTE
Tasa de transferencia sostenida	Hasta 288 MB/S (combined dual-actuator throughput up to ~570 MB/s)
Latencia promedio	4.16 EM
MTBF	2,500,000 horas
Límite de tasa de carga de trabajo	550 tuberculosis/año
Tasa de URE	1 sector por 10^15 bits
Fuerza (Inactivo / Operante)	4.5W / 7.5W
Sealing	Helium-sealed (HelioSeal)
Tamaño del sector	512e or 4Kn
Físico	147.0 X 101.85 X 26.1 milímetro, 690gramo
Temperatura	5C a 60C
Garantía	5-año limitado (fabricante)

MACH.2 Dual-Actuator — Two Drives in One Enclosure

The Exos 2X18’s defining feature is not the laser — it is the dual-actuator design. Two independent actuator arms, each with its own head stack, service two separate 9TB logical volumes on the same platters. The operating system sees two separate drives (da and db), each with 9TB, each capable of ~144 MB/s sustained throughput. Combined, the drive delivers ~288 MB/s — effectively two drives in one enclosure. This doubles sequential throughput per drive bay, which is why the 2X18 is deployed in object storage (MiniIO), backup repositories, and media archives where sequential throughput per bay is the scaling metric.

HAMR vs PMR vs MAMR — The Recording Technology Comparison

Característica	PMR (current standard)	HAMR (Seagate Exos 2X18)	MAMR (Toshiba MG10)
Recording Mechanism	Perpendicular magnetic recording, no laser	Laser heats bits to Curie point before writing	Microwave-assisted, no laser
Areal Density Potential	~2.5 Tb/in2 (practical ceiling)	Hasta 10 Tb/in2 (theoretical), 2.4 Tb/in2 today	~3.5 Tb/in2 (theoretical)
Production Status	Mature, all vendors	In volume production (Seagate)	In volume production (Toshiba)
Capacity Ceiling (2026)	~24TB (PMR-derived ePMR/FC-MAMR)	~30TB+ (HAMR path continues past PMR limits)	~24TB
Risk Profile	Zero (proven)	Low (3+ years of production data)	Low
Best for	All workloads, conservative buyers	Capacity-dense deployments, object storage, respaldo	Mixed workloads, capacity tiers

Plataformas compatibles

SAS 12Gb/s dual-port variant compatible with all servers with SAS backplanes. SATA variant compatible with SATA backplanes. Dell PowerEdge R660/R760/R770, xFusion V7, Lenovo ThinkSystem, MinIO nodes, TrueNAS. MACH.2 dual-actuator support requires OS support: Linux kernel 5.10+ (dm/multipath or two-disk mode), Servidor de Windows 2019+ (two-disk mode), VMWare ESXi 7.0+ (two-disk mode).