InsightaaS: One of the great things about following the IT industry is that it is both broad and deep. We can look at scenarios in which Big Data revolutionizes healthcare on Monday, examine cloud-based collection and storage systems on Tuesday, look at information governance on Wednesday, security on Thursday, and storage media on Friday – and have spent a week discussing a set of connected issues from different perspectives without beginning to exhaust all possible viewpoints.
In the analogy above, today is “Friday,” since we are looking at the physical devices that underpin most of what gets done in enterprises and in the cloud. In today’s featured post, ZDNet’s Rupert Goodwins examines the future of storage systems: flash, disk-based and hybrid. He begins by looking at hard disks, where “developments continue to wring a mixture of increased capacity and either stable or increased performance at lower cost: – developments such as Shingled Magnetic Recording, Two-Dimensional Magnetic Recording, Heat-Assisted Magnetic Recording, and helium-filled disks. Goodwins then moves on to flash, discussing the use of multi-level and Triple-Level-Cell technologies, and use of techniques such as Lowe Density Parity Check to reduce errors.
After examining the two main disk technologies, Goodwins looks at enterprise storage, which “continues to move rapidly to a hybrid model, where similar techniques, architectures and developmental models are applied both within and beyond the enterprise’s traditional boundary between hardware it owns and manages, and services it uses in the cloud.” He also comments briefly on future storage, observing that “there’s no sign of any new disruptive technology to break the flash/hard disk duopoly.” Goodwins closes this extensive review by stating that “even without a revolution in the offing, the foreseeable future of storage is best described by its history: faster, safer, cheaper, more.”
Goodwins’ observations on the disk market are important to infrastructure professionals plotting a course through (and beyond) 2015. They are also, though, a good reminder to all of us who read about, write about and/or work within the IT industry: that the capabilities we take for granted are based on a set of complex and rapidly-evolving technologies, and that the progress within each of these technologies is essential to the ways in which we can apply sophisticated systems to addressing ‘big picture’ issues.
The competition between flash and hard disk-based storage systems will continue to drive developments in both. Flash has the upper hand in performance and benefits from Moore’s Law improvements in cost per bit, but has increasing limitations in lifecycle and reliability. Finding well-engineered solutions to these will define its progress. Hard disk storage, on the other hand, has cost and capacity on its side. Maintaining those advantages is the primary driver in its roadmap.
Hard disks
Hard disk developments continue to wring a mixture of increased capacity and either stable or increased performance at lower cost. For example, Seagate introduced a 6TB disk in early 2014 which finessed existing techniques, but subsequently announced an 8TB disk at the end of the year based on Shingled Magnetic Recording (SMR). This works by allowing tracks on the disk to overlap each other, eliminating the fallow area previously used to separate them. The greater density this allows is offset by the need to rewrite multiple tracks at once. This slows down some write operations, but for a 25 percent increase in capacity — and with little need for expensive revamps in manufacturing techniques.
If SMR is commercially successful, then it will speed the adoption of another technique, Two-Dimensional Magnetic Recording (TDMR) signal processing. This becomes necessary when tracks are so thin and/or close together that the read head picks up noise and signals from adjacent tracks when trying to retrieve the wanted data. A number of techniques can solve this, including multiple heads that read portions of multiple tracks simultaneously to let the drive mathematically subtract inter-track interference signals…
