The Seagate Exos X26z (model ST25000NM000E) is a 25TB host-managed SMR hard drive for storage systems that can manage ZAC zoned storage—not a drive to assume will work in an ordinary desktop, USB enclosure, NAS, or traditional RAID setup. Its SATA connector does not guarantee that a host can use it correctly. Confirm support for host-managed zoned devices and the drive’s full capacity across the entire controller path before buying.
What the Exos X26z is—and who it suits
Seagate identifies model ST25000NM000E as an Exos X 25TB drive and describes it in its Exos Xz SATA SMR Product Manual, 30–25TB (P/N 210157300, Rev B) as a “ZAC Host Managed Zoned device.” That means the host storage stack must understand zoned storage and manage writes according to the drive’s zones. This is host-managed SMR (HM-SMR), not simply a conventional hard drive with extra capacity.
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The drive is intended for professional users who can control and configure the complete storage stack. If you need a drive that behaves as a conventional disk when connected to a typical PC or RAID setup, the X26z is a poor assumption: verify compatibility before purchase rather than relying on the SATA interface alone.
Specifications and the compatibility check
Seagate’s product manual lists the ST25000NM000E with a 7200 RPM rotational speed, 512MB cache, SATA interface, HAMR recording, and ZAC host-managed zoned operation. The manual advises checking with the chosen HBA or RAID-controller vendor to confirm support for the drive’s full capacity.
#1 Best Overall
- 26TB ultra-high capacity for large-scale storage
- 7,200 RPM for sustained enterprise workloads
- SATA 6Gb/s interface for wide system compatibility
- Enterprise-class reliability for continuous operation
- High workload rating for data-intensive applications
Check compatibility across the whole path, not just the operating system or connector:
- Host software: Confirm that the operating system and storage software support host-managed ZAC/zoned devices and can issue appropriate zoned I/O.
- Controller and interconnect: Ask the HBA or RAID-controller vendor about both host-managed zoned support and full-capacity support. Include any SAS switch, expander, or other device between the drive and host in that check.
- Workload: Confirm that the application and filesystem or storage layer can work within the drive’s zoned-write model. Do not assume a conventional random-write workload will behave as it does on a standard disk.
- Product identity and condition: Match the listing to ST25000NM000E, read the seller’s condition description, and check local warranty terms. Seagate’s Exos X product support page identifies the model as Exos X 25TB and provides support-document access; regional support information may change.
StorageReview’s 2023 review describes a specific compatibility experience: the reviewers did not initially detect their sample in Windows or through a server path, but did detect it after connecting it directly to a motherboard SATA port. They attributed the earlier problem to known issues in some SAS HBA, SAS switch, and expander paths. This account is a reason to validate a specific setup—not evidence that every SAS controller is incompatible.
Rank #2
- MASSIVE 28TB CAPACITY – Store and manage enormous datasets with ease. Ideal for data centers, servers, NAS systems, cloud storage, and large-scale backup solutions.
- ENTERPRISE-CLASS PERFORMANCE – 7,200 RPM spindle speed, SATA III 6Gb/s interface, and large cache deliver fast, consistent throughput for demanding 24/7 workloads
- CMR TECHNOLOGY (CONVENTIONAL MAGNETIC RECORDING) – Designed for predictable performance, reliability, and compatibility in RAID and enterprise storage environments.
- BUILT FOR 24/7 OPERATION – Engineered for continuous use with enterprise-grade durability, making it suitable for mission-critical applications and high-density storage arrays.
- STANDARD 3.5” SATA FORM FACTOR – Seamlessly integrates into most enterprise servers, workstations, and NAS enclosures that support 3.5-inch SATA hard drives.
What one published performance test found
StorageReview published its Exos X26z review on December 1, 2023. The publication said its sample came from ServerPartsDeals and was sold as manufacturer-recertified; that describes the review sample, not every drive offered for sale. In its simple fio four-corner test, StorageReview used four threads and a queue depth of 32 to test 128K sequential and 4K random reads and writes:
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Repair Windows errors before they cause bigger problemsFix Now →Scan for outdated or missing drivers - takes under a minuteDriver Scan →| Test | Exos X26z 25TB | IronWolf Pro 20TB |
|---|---|---|
| 128K sequential read | 274MB/s | 278MB/s |
| 128K sequential write | 270MB/s | 286MB/s |
| 4K random read | 2,121 IOPS | 233 IOPS |
| 4K random write | Failed after a cumulative 2 IOPS | 313 IOPS |
These are StorageReview’s results in that review’s test configuration, not guaranteed performance figures for other systems or workloads. The tested IronWolf Pro was slightly faster in the sequential tests, while the X26z random-write test failed. Those four results alone do not establish an overall winner: compatibility with host-managed zones and the intended workload are central to whether the X26z is usable at all.
Rank #3
- Highly reliable performance with enhanced caching—making it the logical choice for cloud data center and massive scale-out data center applications
- Hyperscale SATA model tuned for large data transfers and low latency
- PowerBalance feature optimizes watts per TB
- Proven helium side-sealing weld technology
- Digital environmental sensors to monitor internal drive conditions for optimal operation and performance
Should you buy the Seagate Exos X26z?
Consider the ST25000NM000E only if you can verify that your host storage software supports HM-SMR/ZAC, that every controller and interconnect in the path supports the drive, and that the system can address its full capacity. Also check the actual listing’s model, condition, and locally applicable warranty. Current retail availability, pricing, and any particular Amazon listing are not established by the cited sources, so assess those details on the seller’s current product page.
Quick Recap
Best Value
- 28TB Massive Enterprise Capacity
- 7200 RPM Performance
- SATA 6Gb/s Interface
- 512e Sector Format 3.5-Inch Enterprise Form Factor
- 2.5M-hours MTBF enterprise rating
Rank #4
- 26TB Massive Enterprise Capacity
- 7200 RPM Performance
- SATA 6Gb/s Interface
- 512e Sector Format 3.5-Inch Enterprise Form Factor
- 2.5M-hours MTBF enterprise rating
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