The HGST Ultrastar 7K4000 (HUS724040ALS64) is a SAS 3.5" 7,200 RPM HDD in a traditional 3.5" form factor. The 7K4000 is geared for a multitude of uses in the datacenter, from NAS, RAID, disk-to-disk backup and replication, to cloud storage an Massive Scale Out (MSO) architectures. The 7K4000 comes in capacities of 2TB, 3TB and 4TB.
The 7K4000 is also available in both 6Gb/s SAS and SATA versions, allowing administrators to adjust to the service level required for their individual environments. The SAS interface provides HA (High Availability) features such as failover and multipath, and the more robust feature SAS feature set.
An HDD designed for such a wide range of applications has to offer large capacity, fast consistent performance and a low power threshold to minimize long term TCO. The HGST 7K4000 has a number of features that make it particularly well suited for these applications, beginning with speed.
The SAS version of the 7K4000 we are testing offers up a sustained data transfer rate of 172 MB/s, while the SATA models feature speeds of 171/181 MB/s depending upon the capacity point. The 7K4000 also touts a seek time of 8.0ms delivered via five 800GB platters, an increase of 33% more capacity from the previous 7K3000. Both SAS and SATA drives feature 64MB of cache, though the SAS version uses 512/520/528 sector sizes in comparison to the SATA model with its 4K Advanced Format and 512 byte emulation (512e) and legacy format (512n).
The 7K4000 also features great power consumption characteristics, with 24% lower Watts per GB than the 3TB Ultrastar 7K 3000 predecessor. The focus on power efficiency has spawned five Advanced Power Management modes, which create a 59% reduction in power consumption in comparison to the peak output and can pull a less than 1 Watt total in standby and sleep modes.
After we look at speeds and feeds, the eye turns to reliability, and the 7K4000 does not disappoint. It is designed for 600,000 load/unload cycles and 24x7 usage in multi-drive environments, and to combat the high vibration in server racks, the drives utilize a Dual Stage Actuator (DAS) and Enhanced Rotational Vibration Safeguard (RVS). These enhanced technologies play a part in a standard 1 in 10^15 non-recoverable read bit error rate. The real meat of the reliability picture comes from the whopping 2,000,000 hour MTBF rating. This is nearly double the MTBF of other HDDs in this class, including those used for comparison in our performance testing. This tremendous MTBF results in an AFR (Annualized Failure Rate) reduction of 40%.
Rounding this impressive feature set out with optional TCG Enterprise-A encryption for the SAS models creates a solid, well-rounded product backed by an industry leading five year warranty.