eRacks Systems Tech Blog

HAMR vs CMR: 32TB NAS Drives and What They Mean for Your Storage Budget

A quiet but significant update landed in the eRacks configurator this week: 32TB HAMR drives are now available across the full NAS product line. For organizations that measure their storage needs in petabytes, this matters. The 102-bay eRacks/NAS100 can now be configured with 3.264 petabytes of raw capacity in a single 4U chassis – up from 2.6PB with the previous generation of 30TB CMR drives.

That is not a rounding difference. It is an additional 664 terabytes in the same footprint, with no extra rack space, no additional power circuits, and no change to the chassis.

What HAMR Actually Means

Hard drives have been using conventional magnetic recording (CMR) for decades. In CMR, a write head magnetizes small regions of a spinning platter to store data. The physics of that process set a ceiling on how densely bits can be packed – push the magnetic grains too close together and they become thermally unstable, meaning data can corrupt itself over time.

Heat-Assisted Magnetic Recording (HAMR) breaks through that ceiling by using a tiny laser to briefly heat a precise spot on the platter to around 450 degrees Celsius at the moment of writing. At that temperature, the magnetic material becomes temporarily easier to flip, allowing much smaller, more stable grains to be written reliably. Once the spot cools – which happens in nanoseconds – the written data is locked in place more durably than conventional CMR recording allows.

The practical result is higher areal density: more data per square millimeter of platter surface. Seagate’s current 32TB HAMR drives achieve this without increasing the drive’s physical dimensions. The same 3.5-inch form factor, the same power envelope, the same standard SATA interface – just significantly more capacity per bay.

For NAS applications running ZFS, this translates directly into larger pools, longer time-to-failure curves on RAIDZ arrays, and more headroom before an expansion shelf becomes necessary.

The Capacity Math

The eRacks NAS lineup runs from 4 bays to 102 bays. Here is what 32TB HAMR drives unlock at a few points in the range:

• NAS12 (12 bays): 384TB raw
• NAS24 (24 bays): 768TB raw
• NAS50 (50 bays): 1.6PB raw
• NAS72 (72 bays): 2.304PB raw
• NAS100 (102 bays): 3.264PB raw

These are raw figures. Usable capacity after RAIDZ2 parity and filesystem overhead will be lower – typically around 60-70% of raw depending on configuration – but the density improvement carries through regardless of the protection scheme you choose.

Where On-Premise Storage Still Wins on Cost

The cost argument for owning your storage rather than renting it has not changed, but the HAMR upgrade sharpens it. As a reference point: 100TB of object storage on Amazon S3 Standard runs roughly $27,600 per year in storage fees alone, before factoring in egress charges when you actually retrieve data.

An eRacks/NAS24 configured with enough capacity to cover that same 100TB – with room to grow – starts at $8,995. That is a one-time capital cost. In year two, cloud egress still costs what it costs. The NAS does not send an invoice.

For organizations in regulated industries – healthcare, finance, legal, government – the calculus has an additional dimension. Data sovereignty means knowing exactly where your data is, who has access to it, and under what legal jurisdiction it sits. Cloud storage agreements involve shared infrastructure, third-party subprocessors, and terms of service that can change. An on-premise NAS running ZFS on hardware you own answers those questions conclusively.

Available Now in the Configurator

The 32TB HAMR option is live in the eRacks online configurator for all NAS models. You can select drive size, drive count, RAID level, operating system (TrueNAS, Ubuntu, Rocky Linux, or Debian), and connectivity options at the time of order. Every system ships assembled and tested from Los Angeles.

eRacks has been building custom rackmount storage since 1999. The NAS line ranges from the 4-bay NAS4 at $1,995 to the 102-bay NAS100 at $29,995. All systems are open-source-friendly, built to order, and designed for data center or on-premise deployment.

Configure your system at eracks.com/products/rackmount-nas-servers/ or contact us to discuss capacity planning for your environment.

joe May 15th, 2026

Posted In: FreeBSD, Linux, NAS Storage, NAS24, News, Storage

Tags: 32TB drives, cloud vs on-premise, data sovereignty, HAMR drives, NAS servers, network attached storage, on-premise storage, ZFS

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