ST4000NM0023 Seagate Constellation ES.3 4TB SAS: Fit Guide

The ST4000NM0023 is a Seagate Constellation ES.3 4TB SAS drive, an earlier generation than the Exos line and the SAS sibling of a family that confuses buyers with its numbering. This covers what it is, what it is not, and what to check.

What is the Seagate ST4000NM0023?

A 3.5 inch, 4TB, SAS 6Gb/s enterprise nearline drive from the Constellation ES.3 generation. 7200 RPM class, conventional magnetic recording, 512n sector format, built for continuous operation.

Constellation ES.3 is the generation before Seagate renamed its enterprise line to Exos. It was widely deployed and remains common in arrays still in service.

ST4000NM0023 vs ST4000NM0033: SAS vs SATA

Same generation, same capacity, same platters. The difference is interface.

ST4000NM0023 — SAS. Dual-port, for SAS controllers and backplanes.

ST4000NM0033 — SATA. Single-port, for SATA or SAS controllers.

The trap: a SAS drive does not work on a SATA controller. The reverse usually does. Ordering the 0023 for a SATA-only system produces a drive that does not connect. Our SAS vs SATA guide covers the full comparison, and our ST4000NM0035 guide covers the newer SATA drive in the same capacity.

Why choose SAS at 4TB?

Three reasons, and if none apply, the SATA sibling is cheaper.

Dual-port for multipath in dual-controller arrays or clustered systems. Our dual-port guide covers when that matters.

Backplanes that require SAS, or handle SATA poorly behind an expander.

Matching an existing SAS array. A SATA drive in a SAS array works on many controllers but breaks dual-path redundancy and is generally a bad idea. Our drive lifespan guide covers why arrays should be matched.

Is the ST4000NM0023 CMR?

Yes. Constellation ES.3 drives use conventional recording. Our SMR vs CMR guide covers why that needs confirming on any drive.

Buying used: what to check

This drive is old enough that condition matters as much as specification.

Power-on hours and reallocated sector count, per our hours guide. A Constellation from a decommissioned array may have several years on it.

Whether a full surface scan was done, per our burn-in guide.

Firmware coding. Many ST4000NM0023 drives were sold under HPE, Dell, IBM and NetApp part numbers with vendor firmware. A vendor-coded unit may behave differently on a different vendor’s controller, and a NetApp-coded unit may have a non-standard sector format. Our array drives guide covers this trap.

Carrier, generation-matched. Our caddies guide covers this.

Should I buy this drive or a newer one?

For an existing Constellation array: this drive, matched. For anything new: a current Exos drive at a larger capacity is better value and newer stock. Our spares guide covers holding matched spares for arrays built on older drives.

Frequently asked questions