Seagate’s IronWolf howls out three NASty drives

Seagate has launched three IronWolf NAS drives – an 18TB range-topping disk and two SATA interface SSDs.

Update: IronWolf Pro and Pro 125 sequential write performance differences explained. 2 Sep 2020.

News of the 18TB IronWolf NAS disk drive leaked last week via early retailer listings. The drive spin sat 7,200rpm and features a 6Gbit/s SATA interface backed by 256MB cache and a 300TB/year workload limit for the five-year limited warranty. The 250MB/sec transfer rate makes this the fastest IronWolf disk drive yet.

IronWolf NAS disk drive

This NAS disk drive uses conventional magnetic recording and not the slower write shingled recording technology which could enlarge capacity on the same number of platters. 

The 18TB IronWolf Pro HDD is available this month and retails at $608.99.


SSDs are SSDs are SSDs, so Seagate has NAS-ified the new IronWolf 125 and IronWolf Pro 125 by giving them IronWolf Health Management. This software monitors drive state and alerts compatible Synology, Qnap, and Asustor NAS systems about impending failures.

Meiji Chang, general manager of QNAP Systems, was effusive in his canned quote: “In the unyielding pursuit of innovation, Seagate renews its IronWolf and IronWolf Pro product portfolio, delivering uncompromised endurance and unparalleled performance for versatile QNAP NAS and external storage products.”

The 125s are intended for home and small business user and incorporate a 6Gbit/s SATA interface – no fast NVMe protocol here. Random read write IOPS for the IronWolf 125 is up to 95,000/90,000 and sequential read/write bandwidth is up to 560/540MB/sec. 

The Pro 125 is a tad slower, with random read write IOPS of 96,000/30,000 and sequential read write bandwidth of 545/520MB/sec.

Update: The reason for the much slower Pro 125 sequential write performance s that the measurement criteria are different. Seagate told us;

  • The IronWolf 125 performance spec is based on FOB (fresh out of the box)  performance since this is more of the consumer type NAS SSD.
  • The IronWolf Pro 125 performance spec is based on sustained performance since it is more of a pro/enterprise-grade NAS SSD

Both 125s use 3D NAND flash. The 125 supports 0.7 drive writes per day (DWPD) for its 5-year warranty period while the Pro 125 supports a full DWPD. Consequently it has more over-provisioning and less capacity than the equivalent 125 models.

Prices and capacity points are:

  • IronWolf 125: 250GB ($62.99), 500GB ($83.99), 1TB ($141.99), 2TB ($293.99), and 4TB ($608.99)
  • IronWolf Pro 125: 240GB ($94.99), 480GB ($136.99), 960GB ($262.99), 1.92TB ($472.99), and 3.84TB ($944.99). 

Customers pay a lot for the extra IronWolf Pro 125 endurance and get less capacity and two-thirds less random write IOPS than the IronWolf 125.