ST24000NM002H Seagate Exos 24TB: Compatibility and RAID Guide

The ST24000NM002H is a Seagate Exos 24TB SATA enterprise hard drive, and at this capacity the questions are less about the drive and more about whether your system can use it. This covers what to check before buying one.

What is the Seagate ST24000NM002H?

A 3.5 inch, 24TB, SATA 6Gb/s enterprise nearline drive from the Exos X24 family. It is helium filled, uses conventional magnetic recording, and is built for continuous operation in capacity tiers.

Confirm sector format, exact interface variant and firmware level against the label or Seagate datasheet for your specific unit, since Exos drives ship in several configurations under similar part numbers. Our part numbers guide covers reading the suffix.

Is the ST24000NM002H CMR or SMR?

CMR. Exos enterprise nearline drives use conventional recording, which means it is suitable for RAID, NAS and any array workload.

This matters at 24TB because SMR drives exist at similar capacities in consumer lines, and the price difference tempts people. Our SMR vs CMR guide covers why SMR in an array is a rebuild failure waiting to happen. The Exos is the right class for array use.

Will my server or NAS support a 24TB drive?

The question that stops most purchases at this capacity.

Four things to confirm.

Controller support. Older RAID controllers and HBAs have capacity limits. A controller that tops out below 24TB either refuses the drive or sees only part of it. Check the controller specification for your exact model and firmware — our controller guide covers identification.

NAS compatibility list. NAS vendors publish tested drive lists per model. A 24TB drive may not be on the list for an older unit, and some units restrict drives not listed. Our compatibility guide covers checking.

Sector format. High-capacity drives are 512e or 4Kn. Confirm which your platform supports and match what is in the array. Our sector format guide covers this.

Backplane and carrier. 3.5 inch bay, generation-matched carrier if hot-swap. Our caddies guide covers this.

RAID with 24TB drives: what changes

Rebuild time.

A 24TB drive takes a very long time to rebuild — frequently more than a day under load. During that window a RAID 5 array has no protection, and a second failure loses everything. With drives this size, RAID 6 or equivalent double-parity is the sensible minimum, and the array should be sized with a hot spare.

Our RAID guide covers the trade-offs, and our helium guide covers the one failure mode specific to drives like this and how to see it coming.

ST24000NM002H vs smaller Exos drives

Two honest points.

Price per terabyte is usually best one or two steps below the maximum capacity. A 24TB drive carries a premium for being the largest; 16TB or 20TB may deliver more capacity per dollar. Our 16TB Exos guide covers the smaller sibling.

Rebuild risk scales with capacity. More terabytes per drive means longer rebuilds and more data exposed during them. For a given total capacity, more smaller drives rebuild faster than fewer larger ones, at the cost of bays and power.

Choose 24TB where bays are the constraint. Choose smaller where cost per terabyte or rebuild time is.

When NOT to buy this drive

Performance tiers. A 7200 RPM nearline drive is a capacity drive. Databases and virtualisation want SSD or 10K/15K SAS.

Older controllers with capacity limits, per above.

Behind a vendor RAID controller that validates firmware, where the vendor-coded equivalent is the safer choice. Our OEM guide covers this.

Single-drive use with no backup, because 24TB of unprotected data is a large loss.

Frequently asked questions