The Solid State
The Solid State
From supercomputing to SANs, as memory prices drop solid state disks are looking increasingly appealing to those without unlimited budgets. Greg McNevin reports on the now of solid state storage.
With the meteoric rise of consumer electronics such as digital cameras and mp3 players, the benefits of non-volatile flash memory have overwhelmingly entered our collective consciousness.
Having been around in rewritable forms since the early 1970’s, its benefits have long been known and embraced by high-end, power hungry users. However, for those without access to pockets as deep as the Governments, the magnetic hard drive in its many flavours (IDE, SCSI and now SATA) has been the storage technology of choice.
Solid State Disks (SSDs) have traditionally been used in military, scientific and supercomputing applications where performance and reliability are paramount. The magnetic hard disk however, has long been the storage medium of choice for everyone outside of these circles due to its lower cost and higher capacity.
Processor speeds increased at a rate far outstripping that of storage technology, and the hard disk rapidly became the weakest link in any system. Now that processors are nearing their physical potential for speed they are becoming far less important to a systems overall performance. The speed of storage technologies is what is important now.
Solid Speed
As the SSD market gathers momentum, the cost per gigabyte is decreasing and we are increasingly seeing SSDs being used alongside traditional forms of storage to speed up critical data and applications.
“Magnetic drives are already on death row as physical limitations such as the super-paramagnetic limit and miniaturization challenges stunt advances in capacities.” says Jun Alejo, marketing and communications for BiTMICRO Networks. “Cheaper flash memory and breakthroughs in semiconductor miniaturization are also expected to hasten this succession”
Because it has no moving parts, SSD technology is more rugged and reliable, and can operate at extremes of temperature that would otherwise scratch, burn or freeze traditional magnetic hard drives. It doesn’t have to spin the drive up to retrieve data off the platters so it also consumes less power whilst drastically increasing performance.
And performance is where SSDs become important to contemporary business. Magnetic hard disks may still win every round when it comes to cost per megabyte, however when it comes to SSD, it’s not about price. It’s about speed.
“A lot of people think of the issue being how to store the information. For quite a few years we’ve had the technology to store all the information we need to store. What is really hampering companies, is the ability to make sense of and manage all the information they have.” says Clive Gold, Product Marketing at EMC Australia.
Searching The Abyss
Solid state memory is increasingly being used by organisations with large amounts of frequently accessed data, in high transaction environments, or just anywhere a lot of information needs to be stored and accessed without delay or threat of bottlenecks. Finding the space to store your data is no longer a problem, accessing it is.
“One of the things about using information, is how do you get to it. If you have a terabyte of data for example, how do you sensibly use it to find what you want?” says Gold.
SSDs decrease data access time considerably enabling vast banks of information to be searched in microseconds. This reduces bottlenecks, increases overall server performance and helps make the data itself more valuable through greater accessibility.
Because they avoid the latency issues associated with magnetic spindles, SSD data access time is measured in nanoseconds, rather than milliseconds. For example, the typical access time for a Flash based SSD is about 35 - 100 s. As there is no seek time or rotational latency to deal with, when compared with a magnetic hard disk’s 5,000 - 10,000 s it is rather like comparing a Ducatti motorcycle with a Volkswagen Kombi van.
Light That Burns Twice As Bright?
Magnetic hard disks are prone to wear and tear on their physical components, and even though Flash chips have no moving parts and are much more robust overall, they are still vulnerable to wear after extended use.
Flash chips commonly have around 300,000 write cycles (1,000,000 for the best quality chips) per block. This limit may never get reached by say, a USB memory key which has very low levels of data throughput, however for high-transaction servers or SSDs running applications and operating systems the number or re-writes skyrockets.
To remedy this, Flash manufacturers employ two common solutions to extend the life and reliability of solid state memory. Firstly, they use “balancing” algorithms that monitor the number of times each disk block has been written and spread the writes out accordingly. Second, they have designed “wear-leveling” algorithms that swap data in a block when certain thresholds are reached.
With these measures in place, Flash based SSDs are able to sustain gigabytes of reading/writing per day for several years. This is roughly on par with the average recommended lifespan of a magnetic hard drive. Solid State Disks are overdue for their day in the sun, however, they are in no danger of replacing magnetic drives completely - particularly with recent developments such as perpendicular recording increasing the capacity and consequently lifespan of magnetic disks.
BiTMICRO foresee SSDs becoming more pervasive in enterprise applications, and we may soon see them taking the notebook market by storm. However, SSDs are unlikely to replace magnetic disk drives as the storage medium of choice for at least another seven to ten years. SSDs will remain a complimentary solution, providing the grunt to magnetic disk’s increasingly abyssal storage.
From high end servers to consumer level laptops, solid state disks are becoming far more pervasive in all levels of the industry. There are many players in the market now, some are old hands, some are finding new space to exist as the industry grows.EMC
EMC bills itself as the ultimate information lifecycle management company. One of its mottos is ‘helping customers get the most out of their information’, and one of the ways it does this it through effective deployment of solid state solutions. EMC has always used solid state memory caching in its systems to increase performance.
Texas Memory
Avoiding any ‘bigger than’ puns, the name Texas Memory is synonymous with high end solid state applications. Its RamSan-400 server was recently deployed by CCP Games to manage its multiplayer internet game EVE Online. CCP achieved an immediate 4000% increase in performance and reached a record 17,000 concurrent online players.
BiTMICRO
US based BiTMICRO Networks develops flash disk, solid state disk (SSD), network storage and file cache solid state storage solutions for high end applications. With SSDs optimised for notebooks, desktop pc’s, and servers, it focuses on markets such as finance, medical and the military where reliability and performance are critical.
Samsung
A household name for consumer electronics, Samsung is also a major player in the storage market supplying both magnetic hard drives and solid state memory. Samsung recently announced its first consumer orientated NAND based SSD for notebook computers.
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