Seagate ST20000NM007D 20TB 7200RPM SATA 6Gb/s 3.5in Exos X20 Hard Drive

The Seagate ST20000NM007D is the 20TB SATA model of the Exos X20, a helium-sealed 3.5-inch enterprise hard drive running at 7200 RPM with a 256MB cache. Seagate's data sheet lists it as a CMR drive with a sustained transfer rate of up to 285 MB/s and an MTBF of 2.5 million hours. This part number is the standard version, without self-encryption.

At 20TB per bay, the drive is aimed at buyers who need to add petabytes without adding racks: backup and archive tiers, object storage, video and imaging repositories, and large NAS or JBOD expansions. Like other nearline drives it is rated for a workload of up to 550TB per year, according to Seagate's product manual. That is plenty for capacity tiers, but random-I/O workloads such as busy databases belong on 10K SAS drives or flash.

The interface is single-port SATA 6Gb/s. SATA keeps cost down and works with onboard SATA ports as well as most SAS controllers. Choose the SAS model, ST20000NM002D, if your enclosure depends on dual-port SAS for controller failover. The drive is delivered in 512e format for broad compatibility. You can convert it to 4Kn with Seagate FastFormat, but the routine erases all data, so set the format before deployment and keep every drive in a RAID group on the same format.

Before ordering, confirm these details:

• The ST20000NM007D is a bare drive. Hot-swap servers and NAS units need a tray or caddy for each bay.
• HPE and Dell servers use OEM carriers and may flag drives without their own firmware.
• If policy requires encryption at rest, order the SED model ST20000NM000D instead.
• Check your NAS or controller vendor's compatibility list for 20TB drives, since older firmware may not recognize them.