Western Digital claims to have produced a hard drive with the largest capacity at the moment. The 15 TB Ultrastar DC HC620 is the successor to last year’s 14 TB Ultrastar Hs14.
Like the Hs14 of a year ago, the Ultrastar DC HC620 is filled with helium. This has the advantage that the individual discs (eight in total) can be placed closer together and experience less resistance.
To further increase the storage density, WD uses shingled magnetic recording (SMR). Thanks to SMR technology, the tracks can overlap on a disc, similar to slates on a house. The only disadvantage is that re-writes are slower because data has to be written sequentially, so that no information is destroyed on the overlapping tracks.
It also means that the data writing software on the host must be modified to be compatible with SMR. So you can’t just use the new 15TB drives as replacement copies for non-SMR drives.
7 percent more capacity
According to WD, the new drive is optimized for sequential write commands and is particularly suitable for hyperscale data center operators who need to manage large amounts of information from sources such as video surveillance and big data.
The new 15 TB drive adds 7 percent capacity compared to its predecessor. A 4U exposure with 60 of these drives can store up to 900 TB of data, compared to 840 TB with the 14 TB drives. In a rack with 10 enclosures, you can thus lose 600 TB extra.
The data transfer rate is 255 MB/s compared to 233 MB/s on the Hs14. Furthermore, the new HC620 has the same buffer of 515 MB and rotation speed of 7,200 rpm. The drive uses a 6 Gbit/s SATA or 12 Gbit/s SAS interface.
Both Seagate and Toshiba are already offering 14TB drives today, which suggests that they will soon come onto the market with 15TB as well.
Earlier this week, figures from IDC showed that Seagate today leads the market for high-capacity HDDs in terms of the number of copies shipped, but Western Digital does deliver the most capacity.our launch article.