Seagate Exos X18 18TB Now on the Market in Volume

Seagate Exos X18 Cover
Seagate Exos X18 Cover

Seagate announced another milestone in increasing capacities. The Seagate Exos X18 18TB hard drives offer more storage in the traditional 3.5″ form factor. As storage needs continue to increase, especially driven by the amount of video, photos, and machine data being produced, capacities need to increase accordingly.

Seagate Exos X18 18TB Features

Seagate Exos X18 drives come in 18TB or 16TB capacities. We also get either SAS 12Gbps or SATA III 6Gbps interfaces on the helium-sealed drives. Adding to SKU complexity, there are also SED and SED-FIPS (on SAS HDDs) models available. The Exos line is the higher-end data center drive series from Seagate, but the Seagate IronWolf Pro 18TB HDD is already out from the company.

Seagate Exos X18 18TB Angle View
Seagate Exos X18 18TB Angle View

The new Exos X18 line spans is a 7200rpm spindle rate drive that can handle up to 270MB/s. That is important since it means a single drive can more than saturate two 1GbE NIC ports and almost a full 2.5GbE port. While these drives will seldom be used in a server designed for a single drive or a single 1GbE networking, it also means a standard 1U 4x 3.5″ bay chassis will, in theory, be able to saturate 10GbE with hard drives. These are really for sequential transfers as 4K random IOPS are more than 2000x lower than modern NVMe SSDs such as theĀ Kioxia CM6 PCIe Gen4 SSD we reviewed.

The drives come with a five-year warranty and offer a MTBF of 2.5M hours with a 0.35% 24×7 AFR figure. Non-recoverable error rates on these are 1 in 10^15 which his normal for 3.5″ hard drives but are also 1-2 orders of magnitude higher than on SSDs.

Seagate Exos X18 18TB Specs

Here are the key specs for the Exos X18 line:

Seagate Exos X18 Spec Table
Seagate Exos X18 Spec Table

Something that we wanted to point out, especially given ourĀ WD Red SMR vs CMR Tested Avoid Red SMR and series, is that Seagate is clearly calling out the CMR technology. This is a trend at Seagate that we like, although it has been common in the data center market to do so.

Final Words

Seagate says that the Exos X18 18TB hard drive is available now at a $561.75 per drive MSRP. We always welcome larger hard drives but something that has become increasingly clear is that data is being generated at a much faster rate than hard drive capacities are increasing. We covered the Seagate Exos X16 IronWolf 16TB and IronWolf Pro 16TB Shipping about five quarters ago. A 12.5% annual increase in capacities for the Exos line is significantly slower than the annualized data growth rate projections in the industry. This is an area where the lack of competition in the industry, and difficulties in achieving capacity breakthroughs has largely stagnated capacities.


  1. @Bob,

    i guess Seagate should have continued the canid theme they began with the IronWolf, and given the Exos the name SledDog instead :)

  2. One has to wonder.

    The power, cooling, and rack space savings of a 1U 36x E1.S with either 15TB or even 30TB may very well be worth every penny … when they finally become a lot more mainstream. 1PB in 1U with a pair of dual-port 100GbE pNICs via AMD EPYC Rome is viable here.

    30TB SAS Small Form Factor is another option in 2U 24 bay servers. That’s 720TB in 2U. Again, AMD EPYC and a pair of dual-port 100GbE pNICs.

    We’ve seen promise of NAND based drives larger than 8TB on and off for years now.

    We’re still waiting. :S

  3. @Phillip
    There are now SSDs in the 3.5″ form factor that reach capacities of 16TB – 64TB at a fairly reasonable price of $3K – $10K.


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