It isn’t making solid sense, not just yet. We are talking about solid state storage, the technology that has been around for years, but still hasn’t made inroads into the enterprise space in any major way. On the face of it, the technology makes a lot of sense. No moving parts, storage made from silicon chips, no spinning metal platters or streaming tape. This means increased durability, faster access to data. Yet costs are still high, which has slowed adoption in the enterprise.

But there is much more than meets the eye. Let’s explore where we are headed in this type of storage.

Benefits
Better access times: Compared to hard disk drives (HDD), flash memory offers faster access times and lower latencies. So while capacities of HDDs have grown exponentially, their read/write access times have not improved in a similar fashion. Meanwhile, the processing power of servers has been increasing, so the data access latency increases. Solid state storage comes as a useful alternative here as it offers access times that are 100 to 1000 times that of drives with mechanical parts. It offers higher bandwidth throughput as well. Because of this, solid state storage offers very high random nput/output per second (IOPS) performance.

Lower price/IOPS: The upfront costs for solid state storage devices can be huge, and working out one-to-one per terabyte costs versus HDDs will tilt the balance heavily towards the HDD side. But proponents of solid stage storage say that is the wrong parameter to base your decisions on. Instead it should be price/IOPS, where solid state storage scores higher over HDDs.

Reduced energy costs support green initiatives: Solid state storage devices use less energy as they don’t have any mechanical parts that need to be moved. This leads to lower cooling needs. And they are silent as well. But before diving into taking up solid state storage, do assess the way in which you would be using it for your kind of business. In case you need to opt for DRAM to enable faster write processes, the batteries to power the DRAM environment will have to be factored into your power and cooling needs.

Ashok K Gupta, Chief Information Systems Manager, Indian Oil Corporation, says “If questions related to energy efficiency are raised, solid state is the answer. But today, it is not available off the shelf. Hence, we will have to wait for some time to replace conventional hard drives with solid state drives.”

In various forms: You can have solid state storage on form factors of HDD, so that you can continue to use your existing storage arrays. At the same time you can also have them in other forms as well that can take smaller form factors.

Harish Shetty, Executive Vice President, HDFC Bank says, “Solid state drives will have limited usage because of the difference in costs. Wherever there are challenges with data centre infrastructure and performance is a big concern, SSD will definitely be an option. We foresee an increase in adoption of SSDs and consequently a drop in their prices.”

The flip side
Costs are still high: While the costs for solid state storage devices have been coming down steadily over the years, they still remains high, as far as most vendors are concerned. “Anybody would like to switch to SSD, as soon as the costs come down. The present cost is many times higher than motorised hard disks. We may start switching over to SSD when the cost is around two times that of the HDD,” says Gupta.

Price/capacity scores will remain low: As is the case, the price of HDDs have been falling too, especially for higher capacities. So price per GB has been falling. Solid state storage is still very expensive, so in price per GB comparisons, hard drives will score phenomenally better than solid state storage.

But prices will come down in the long run. In January 2010, in its worldwide 2009-2013 Solid State Drive Forecast Update, IDC said, “Pricing remains a key metric for SSD adoption in all market segments. The slowdown in IT spending over the past 18 months has led to production cutbacks in NAND semiconductors, subsequently slowing overall SSD price reductions. However, the long term decline in the cost of NAND memory will translate into lower price points for SSDs. These lower price points, coupled with increased SSD capacities, will make them a compelling alternative to HDDs in certain market segment.”

Complex write process: Reading flash memory is rapid, but one cannot say the same thing for the write process, as this process is more complex, and takes longer. For enterprise-class storage, faster writing is enabled by using an intermediate cache to hasten the processes up, or using multiple flash chips in parallel, which would be faster than going the sequential way. However, this may not be the right solutions for all businesses.

Reliability: Issues have been raised about the performance, endurance and reliability of flash memory devices. Over the years, solid state storage devices have improved on all these grounds, and now build in clever controllers that enable better performance and endurance of the memory.

Teamed up with HDD

Solid state drives are not going to replace HDDs in the enterprise space anytime soon. They will co-exist. In fact new storage virtualization offerings build in support for SSD arrays now, thus strengthening their entry into data centres. IDC also believes that SSDs complement HDDs for certain applications. The desire for increased performance, better utilization, faster access times, and lower power consumption is providing an increasing opportunity for SSD-based solutions in those data centres where there is a premium on high performance.

The area that SSDs are replacing HDDs is short stroking, a way in which storage administrators leave the outer areas of hard drives empty to enable faster reads. This means that there is a lot of unused space across all HDDs. Replacing them with fewer SSDs turns out to be more optimal, improves performance significantly, and takes up lesser space.

In a company, there would be loads of data which needs to be stored, but is not accessed frequently. For many applications, your current storage media would work just fine. SSDs will find favour wherever speed is of essence. But if you also need to write data fast, you would have to look for ways to blend conventional devices, SSDs and DRAM to meet your needs.

Storage Networking Industry Association (SNIA) identifies some killer applications for solid state storage. Flash SSD is best for business notebook computer storage, while cached flash RAID SSD’s killer applications are data warehousing, video on demand, seismic processing and rendering. DDR RAM SSD is great for write-intensive online transaction processing, web transaction databases, mission critical data warehousing, etc.

Neeraj Pal Singh, Senior VP and CIO, Aditya Birla Group believes, “Solid state drives can be exploited for lower capacities and come with the promise of improved reliability, speed and energy efficiency. However, its cost/performance and scalability claims are yet to be proven. Longer term sustainability and the technology roadmap for storage technology require innovative technology backed by a holistic solution offering and solid state drives are yet to mature in these respects.” Shetty also concurs, “The current challenges are with most vendors taking time in designing their storage boxes with SSDs. We hope to see a major change in this space soon.”