Setting Your Sights on SSDs

At the beginning of 2008, I, like many, was skeptical of using Flash technology in enterprise-class storage systems. My concerns were that users would not implement the drives due to their higher cost compared to spinning hard drives, their widely known limitations on rewrites, and no proven implementation record in mission-critical environments. In addition, I had heard some real horror stories over the past few years of laptop users with Flash and their data loss when the flash memory malfunctioned. As we all know, enterprise storage contains the life of business -- information -- and mission-critical application environments have grown accustomed to 24x7xforever operations.

Okay, I know there are other companies providing Solid State Disk (SSD) storage systems, such as Texas Memory (for 15 years), and, as a matter of fact, there are a number of drive and SSD technology suppliers already in the business and others about to announce new advancements in the technology as a whole. So, if I know all this, then I expect technology leaders of companies such as 3PAR, EMC, Hitachi, HP, IBM, Sun, and others to be well up-to-date on advances in solid state technologies and the nuances associated with the recording medium. Otherwise, I am left to believe they are stuck on spinning disks and do not understand the market forces at work that drive the need for speed and increased use of flash drives within enterprise-class storage products with enterprise-class reliability and resilience.

Rather than opine quickly in early 2008 on technical concerns and user acceptance, I watched, read, listened, and learned and did some basic research with vendors and users. I watched a number of vendors discuss flash drives at conferences (the goodness of them, the danger of them, and the industry-changing nature of them). I read blogs and articles that were informative, factually incorrect, and sometimes downright funny, and I listened to podcasts and presentations from vendors that provided a number of different views -- a learning experience, to say the least.

What did I learn?

I learned that Sun Microsystems has structured ZFS so it can be used effectively with SSD subsystems (primarily for use with its OEM’d LSI storage product and resold HDS systems in Q4 -- but a good thing because, in my opinion, there will be more third-party SSDs attached to Sun than Sun-sold SSDs). It is not clear that Sun understands the business forces at work driving price changes in SSD -- it is not iPods and thumb drives (a very different use of flash memory).I learned that large server and storage providers are still trying to wrap their arms around flash drives and solid state disk -- seems they may be harkening back to yesteryear when SSD was big and bulky and so overly priced that the ROI had to be enormous in order to even consider a 15-minute sales pitch. These vendors may be caught short as flash drive technology quickly evolves around them -- and what may now be innovative subsystem solutions become outmoded by drastic drive wattage reductions and phenomenal application response times.

I learned that my skepticism of EMC putting flash drives in the Symmetrix platform was healthy because it pushed me to learn more about EMC, and how they implement the technology to meet enterprise-class requirements.

Typical for EMC, they were working quietly with STEC (a quality flash drive provider) for some time, to prepare a STEC flash drive that meets the requirements of enterprise class utilization.

The question EMC and STEC faced: How do we increase the typical tens of thousands of write operations average? In addition, how do we increase the resilience of flash drive configurations so that they meet, or exceed, subsystem warranty periods?

Next Page: More thoughts on FlashThe answers came by way of leveraging the use of the standard STEC ZeusIOPS advanced recording technology, capacity provisioning, and wear-leveling technology. From the data recording perspective, consumer use of flash memory uses multilevel cell recording technology (2 bits or more per cell). STEC enterprise-class drives use single-level cell recording technology (1 bit per cell). SLC provides longer-term bit reliability and higher performance.

The STEC flash drive caters for capacity by over-provisioning of actual capacity (i.e., a 73 Gigabyte flash drive actually contains 146 Gigabyte of memory space). This over-provisioning technique is ideal for providing more write space. Combining SLC with over-provisioning of storage assists in bringing the write capabilities to the hundreds of thousands of write operations capable in this instance of flash drive technology.

Topping it all off, EMC optimizes the way it accomplishes I/O to the drive to take advantage of the STEC drive attributes and its configuration within the Symmetrix platform.

In combination, SLC recording, extra capacity, a unique wear level algorithm, and I/O optimization have enabled EMC to prove the reliability and resilience of enterprise-class flash drives within the Symmetrix storage platform.

What about the market acceptance factor I mentioned early on in this blog (by way of avoiding flash drives due to higher costs)? Well, we are nearly six months into EMC shipping flash drives, and, while EMC does not provide unit shipment numbers or penetration rates (flash drives per Symmetrix shipped), I have spoken to users who have the flash drives installed -- they are blown away by the performance, and they feel that the drastically reduced response time was well worth the additional cost for the application users. EMC has indicated to these users that the price of the drives will come down over time, and I believe there has already been a slight decrease in purchase price since introduction.What about Flash Drives in storage system such as CLARiiON, IBM DS4000, LSI, and Sun 6X40?

Clearly, Sun, Hitachi, and others are intending to deploy flash drives within mid-tier product offerings. Press is reporting that EMC will implement flash drive technology in the CLARiiON platform soon; however, cost factors and the mid-tier market users will dictate the adoption/acceptance rate of flash drives.

There are plenty of SMB mission-critical applications that can benefit from the performance increase provided by flash drives. In fact, this kind of technology in the SMB space may have a game-changing effect for a business and provide a competitive edge for the early adopter.

Are server vendors using Flash inside the servers?

You bet they are, and one of the best places to implement flash technology is within a blade server to increase the effective utilization of the processor and accomplish write tasks faster. I anticipate HP, Sun, IBM, and others to increasingly use flash memory as cloud computing becomes more the norm over the next three years; however, I encourage them to look closely at what STEC has done and build in the reliability, provisioning, and resilience required for enterprise-class utilization.Finally

Flash technology and Flash Drives are not coming… They are here! Moreover, they're here to stay! The balance of 2008 will see many vendors follow EMC’s lead with Flash drives in the enterprise platform; however, I anticipate 2009 to be a year of some user confusion over flash. The smart vendor will educate those confused users.

The Trainer Test results: EMC dared to dip its toe in the water and, yes, they are proving flash drives can have enterprise-class resilience.

— Tom Trainer is founder and president of analyst firm Analytico. Prior to founding Analytico, Trainer was managing senior partner at Evaluator Group, and has also worked at EMC, HDS, Auspex, and Memorex-Telex during his 30-year career in IT.

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