The Seagate Exos X24 ST24000NM007H is a 24TB SAS hard drive with two data ports. It spins at 7200 RPM, has a 512MB cache, and sustains up to 285 MB/s. Helium fills the sealed case, and CMR recording keeps rewrites steady.

What SAS adds to the X24

• Two ports. Each port has its own SAS address and runs at up to 12Gb/s. Two controllers can reach the drive, so a second path stays open if one fails.
• More sector sizes. The drive formats to 512, 520, or 528 bytes, or to 4096, 4160, or 4224 bytes. Some arrays need those sizes. Changing the size is a low-level format, and it erases the drive.
• Speed headroom. Each port moves up to 1200 MB/s, or 2400 MB/s for both. The drive sustains 285 MB/s, so the link is rarely the limit.
• Array fit. Dual-port SAS is what most dual-controller storage arrays expect.

The SATA X24 has one port, runs at 6Gb/s, and can't format to 520 or 528 bytes. A SATA-only port also can't run this SAS drive.

One caution. Branded arrays such as the HPE MSA support only their own drives. Check your array's drive list before you pick a plain Exos drive.

The five Exos X24 24TB models

All five share the 24TB size, the 7200 RPM spindle, the 512MB cache, and the 285 MB/s speed. Pick a self-encrypting model only if your policy calls for hardware encryption. Seagate notes that those drives may need a TCG-compliant controller.

ISE stands for Instant Secure Erase. It lets you wipe the drive in seconds before you retire it.

Power and capacity

Seagate lists 6.5 W at idle, so a twelve-bay chassis idles near 78 W. Under a mixed random load the drive draws up to 9.8 W. Those twelve bays hold 288TB raw, and RAID 6 leaves about 240TB usable. A full pass over 24TB at the rated 285 MB/s runs about 23 hours.

ST24000NM007H specifications