A solid choice

Just about everyone has heard the hype surrounding solid-state drives, but only now are we starting to see SSDs get a foothold as a storage alternative. The market is flooded with options, and the performance we've seen from several of the latest drives back up some of the claims that SSD supporters have made about the technology's advantages.

SSD storage consists of NAND flash-memory chips. SSD's lack of moving parts gives it an edge over regular drives on multiple levels. First, SSDs are more shock-resistant than magnetic hard-disk drives; SSDs have fewer potential points of mechanical failure, and are able to withstand jostling and sudden impacts. Second, SSDs are silent, which makes them great for PCs that sit in living areas. They also generate less heat and use less energy, so they don't require fans, which contributes to their quiet operation as compared with a spinning hard-disk drive. Finally, because of their compactness, SSDs can be designed to fit in tight spaces.

IDC forecasts the market for SSDs will grow 70% between 2007 and 2012, but adoption of this new storage infrastructure will not happen overnight. SSD provides the power to significantly increase IOPS for the most demanding applications. It also frees up overtaxed traditional drives in tiered storage environments to function at maximum ability. Tiered storage moves data between high-performance, low-capacity drives and slower, higher-capacity drives.

“There are currently two driving forces for SSDs in the enterprise. The first is regarding performance hungry servers which currently require a large number of server class HDDs in order to meet both the demand on IOPS and reliability. Organisations with this demand are now looking into replacing some HDDs in this application with high-end SSDs that have high IOPS, and retaining HDDs for storage and less demanding environments,” says Steve Hall, Flash Product development manager, EMEA, Kingston Technology.

The current demand for SSDs is primarily driven by applications that require high performance and low to medium capacity. Can SSD emerge as the primary storage technology in the data centre? “Fundamentally huge performance improvement, and power consumption reduction will drive the adoption of SSDs in enterprises. It won’t be the primary storage technology in data centres because of limited capacity. However, as costs reduce over time it will be used as the main storage disk for applications requesting high performance,” says Mohamed Halawa, Enterprise Marketing Manager, Dell Middle East.

SSDs have the speed, but HDDs have the capacity.Though per-gigabyte prices for HDDs and SSDs are dropping at the same pace- about 50% per year- there is still a sizeable price gap between the two. Both magnetic and solid-state technologies are complementary in enterprise applications, especially in emerging tiered-storage architectures, says Khwaja Saifuddin, Director Sales MEA, Western Digital. “ Solid-state drives have application in multiple markets and are complementary to magnetic hard disk drive products. We expect growth in digital content to drive increasing demand for both magnetic and solid-state drives into the future.”

Increasing speed of operation and access to critical applications is the impetus for investing in solid state technology. So once the hardware decisions are made you have to address the software questions. Two storage virtualization technologies noted for their ability to make the SSD performance spike are thin provisioning and automated tiered storage. On top of these, you should also employ storage resource management (SRM) software to automatically track and report how much capacity is being used across tiers, and by the SSDs themselves. The SRM software should provide granular enough detail about utilization to take the guesswork out of SSD capacity planning.

This leads to a question everyone should ask: Are there hidden costs? Many solutions require investment in entire “bricks” and enclosures, which significantly increases the investment. Others allow you to purchase SSDs in smaller increments as the data set grows.

Additionally, will you be forced to predetermine volumes and applications for SSD technology? Can you use thin provisioning with the SSDs, or are you wasting capacity just to allocate storage? Thin provisioning means space is only consumed on these expensive drives when data is written, leaving as much space free as possible and the drives operating at peak performance. While thin provisioning is gaining popularity, few vendors offer the technology for SSDs.

Another consideration is the ability to automate storage tiering. Incorporating SSDs can improve performance, but without the ability to dynamically move data to lower storage tiers, unused data remains static on the high-performance drives. This quickly negates the anticipated benefits. Because industry research shows that 70% to 80% of all data is inactive at any given time, automated tiering helps keep business data online, while removing the need for administrative intervention or data classification software, saving time and money.

By combining thin provisioning with automated tiered storage, users can maximize utilization of SSDs for business-critical applications.