The Enterprise Storage world seems forever abuzz with new technologies claiming to be the new solution to all of the business drivers. It is often easy to overlook that the humble disk shelf is still a key foundation stone of virtually all enterprise storage solutions. While the latest NVMe SSD technology has its rightful place as the primary data tier for the HPC market, just as tape does for the “file and (hopefully) forget it” lowest tier, disk storage squarely occupies the middle ground. This is reflected in the latest worldwide analysis of disk shipments by market1. Overall, HDD shipments are declining, but those for nearline storage are showing steady year on year growth reflecting the fact that nearline disk-based storage systems provide an optimal blend of high capacity, low cost storage performance. In fact, when you consider the significant technical challenges to deliver a truly reliable Enterprise Class storage array there is little to justify calling the engineering involved humble.
The rotating disk drives used in high density storage systems are a miracle of electromechanical design. The heads that read and write the data to the disks fly at an incredibly small but finely controlled height above the rotating disk – a matter of just a few nanometers. When you consider that an average human hair has a diameter of 100 microns, which is 100,000 nanometers, you begin to understand just what a small distance that is. Needless to say, like anything else designed to fly, high speed contact with the ground (in this case the disk surface) does not have a good outcome!
Data storage system reliability is derived from many more factors than the disk drive itself and is a product of the quality process undertaken by only the most reliable manufacturers in the design, manufacturing and testing of storage systems. Some of the key differentiators that help Nexsan deliver long and reliable operation are Anti-Vibration DesignTM, Cool Drive TechnologyTM, Active Drawer TechnologyTM, intensive drive testing, and precautionary disk handling and shipment methods.
To reduce the rate of failure and ensure enterprise-class reliability, Nexsan has created a rigorous set of automated test programs to isolate weak and marginal drives. And every disk drive goes through multiple days of this testing as part of the production process of every storage system. The media test cycle validates, and if necessary, repairs every sector of the drive. In the case of a 12TB disk, this is the equivalent of spell checking every word in 4,000 copies of Tolstoy’s War and Peace! However, if more than 50 sectors are flagged for correction, the disk is rejected. This represents a 99.999998% standard for a disk to be qualified. The stress test moves the read/write heads of the disk to the inner and outer diameters of the disks more than five million times to validate the disk’s actuator servomotor and positioning electronics. Through all testing, the disk is constantly monitored for read/write, SCSI interface, link speed or performance issues that may indicate underlying issues.
Innovative design, quality manufacturing and rigid testing are all targets of any great storage vendor. Some vendors may point to a single capability they excel in, Nexsan engineering stands apart as a leader in all three. Nexsan constantly scrutinizes every step of the quality process for optimal delivery of the highest level of reliability which Nexsan has been delivering for 20 years. The combined excellence in engineering and development of enterprise-class products along with of our customer focused service means that Nexsan users always get the quality they need along with the energy, space and cost efficiencies necessary to compete in a new economic and technological environment that demands reliable and highly efficient storage.
Grahame Morrison, E-Series & Beast Product Director