Beyond NAS, Seagate lists the IronWolf Pro as ideal for video production, workstations, and servers. The Exos X20 is rather ideal for data centers, big data applications, distributed file systems, surveillance, backup, etc.
Seagate’s Exos X20 and IronWolf Pro 20TB mechanical hard drives have a capacity of 20TB and use nine platters that spin at 7,200 rpm, making them well suited for relatively fast bulk data storage. The Ironwolf drive targets NAS and workstation users, while the Exos-branded drive is designed for enterprise use, meaning these are high-end drives designed for multi-disk environments .
Achieving this kind of capability often requires new recording technologies, such as energy-assisted magnetic recording (EAMR) via heat-assisted magnetic recording (HAMR) or microwave-assisted magnetic recording (MAMR) . The idea in both cases is to facilitate the process of writing data to the magnetic surface by using some form of energy to enable the magnetization of ultra-tiny bits on the platter, with HAMR using lasers and MAMR using microwave.
Alternatively, overlapping write tracks on the platter allows for higher density in a process known as shingled magnetic recording (SMR). However, this causes a performance hit, especially when writing data, due to the reorganization needed in the background. SMR drives remain popular for certain workloads that benefit from a lot of idle time, such as backups and archiving.
Seagate was able to use the conventional Perpendicular Magnetic Recording (CMR/PMR) technique with these drives, so it doesn’t use the more exotic recording technologies. These types of disks perform best, but it is also possible to use multi-actuator technology (providing independent data paths) to increase performance and density.
Potential competitors include WD’s 20TB OptiNAND drives which rely on energy-assisted perpendicular magnetic recording (ePMR) and use flash memory (NAND) on the hard drive to store and retrieve small bits of data, thereby improving performance.
Seagate, for its part, believes that NAND is not the way to go for its target markets. Both approaches use discs filled with helium which is more than seven times thinner than air. This allows the platters to spin more easily and with less friction. According to WD, helium-based drives also run cooler and are resistant to humidity. As a side effect, capacity and reliability can be increased while having higher efficiency due to lower power consumption. Let’s see what it looks like in action.
|Product||Seagate Iron Wolf Pro||Seagate Exos X20|
|Capacity||20 TB||20 TB|
|Cost per GB (rounded)||$0.030||$0.025|
|Sustained transfer rate||285Mbps||285Mbps|
|Hidden||256 MB||256 MB|
|Workload assessment||300 TB/year||550 TB/year|
|guarantee||5 years||5 years|
These two drives are very similar internally but are suited for different markets – the IronWolf Pro is aimed at NAS and workstations, while the Exos X20 is aimed at enterprise racks.
NAS, or network-attached storage, is especially useful for small and medium-sized businesses (SMBs). Beyond NAS, Seagate lists the IronWolf Pro as ideal for video production, workstations, and servers. The Exos X20 is rather ideal for data centers, big data applications, distributed file systems, surveillance, backup, etc. Either way, Seagate offers very high peak capabilities while promising consistent reliability and performance. Both drives have environmental sensors for purposes such as measuring rotational vibration (RV), but the Exos X20 focuses on efficiency with trademark PowerChoice and PowerBalance features while the IronWolf Pro is optimized for the NAS with AgileArray.
Both drives currently cost about the same, which isn’t surprising considering they have similar hardware. Of course, the price per GB is quite high, paid as a premium to get a CMR at such a high capacity.
Both drives operate at 7200 rpm with a maximum sustained transfer rate of 285 MB/s and contain 256 MB of cache. While both come with SATA connectivity, the Exos X20 is also available with the 12 Gbps SAS interface. Due to the segmentation of these drives, the Exos X20 has a higher mean time before failure (MTBF) of 2.5 million hours compared to IronWolf’s 1.2 million, and a workload of 550 TB per year versus 300 TB per year for the IronWolf Pro. Both discs are guaranteed for 5 years.
Software and accessories
The IronWolf Pro comes with two additional features: the IronWolf Health Management (IHM) system and three years of Rescue data recovery services. The HMI can be enabled for a NAS system to add “prevention, response, and recovery recommendations to ensure optimal system health.” The Services offer in-house facilities with a claimed recovery rate of 95%.
To look closer
These are your standard, user-friendly 3.5-inch format hard drives. The labels are a bit different but are otherwise subtly attractive. Ours both use a SATA 6Gbps interface.
Here we have the control board with connectors, using a foam protector.
We can identify three main components: the spindle motor controller, the main drive controller, and the cache. The spindle motor controller is essential to the mechanical operation of the drive and is labeled SMOOTH VIKING; STMicroelectronics manufactures this VIKING-like SMOOTH chip. Seagate’s main disk controller is the 500051851 and is reminiscent of the microcontrollers used for solid-state drives (SSDs), which are often ARM-based.
The cache is K4B2G1646F-BYMA, which is Samsung DDR3L. DDR3L operates at a lower voltage than DDR3 and therefore uses less power; this particular module is 2GB (256MB) in a 128M x 16b configuration. Cache on an HDD is not the same as on an SSD, as it is generally used for metadata rather than writing data to an SSD, although the NAND on WD’s OptiNAND hard drives is, in fact, , used for metadata.
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