Using Solid State Drives (SSDs) in AdvancedTCA Applications

By Gary Drossel, Western Digital

As their cost per gigabyte (GB) continues to decrease, SSDs are appearing as hard disk drive (HDD) replacements in AdvancedTCA applications. However, to determine the optimal choice for a particular situation, OEM designers must thoroughly evaluate their storage options based on performance, usage model, and budget considerations.

SSDs are not just replacements for HDDs. They are often complementary technologies, with both finding places in a single application. 

The top factors governing storage selection are as follows with cost being an obvious factor in all cases:

• Performance - measured in megabytes or input/outputs per second (IOPS)
• Reliability – measured in high availability and product lifetime
• Power consumption - measured in watts
• Capacity - expressed in gigabytes

In applications where speed is a major factor, SSDs win with read/write speeds in the 250 MB/s range as compared to 125 MB/s for HDDs. This is the key for media streaming and digital graphics equipment requiring high data rates with no interruptions, stops, or stutters.

With no moving parts, and impervious to extreme temperature, shock, and vibration, SSDs provide very high reliability, which is required for TEM carrier-grade applications as well as military, defense, aerospace, and industrial systems. In addition, advanced solid state storage technologies are now available that deliver real-time data on SSD useable life to eliminate unscheduled downtime and forecast endurance in months or years

SSDs generally consume less power than HDDs.  How much is based more on how the drive is used than on the raw HDD peak and idle power specifications. SSDs in the data center clearly outperform HDDs on performance or a transactions per watt basis.  When SSDs are used in notebook computers, their lower power consumption can produce 5 to 30 extra minutes of battery life, depending on the type of microprocessor and screen.

When evaluated on cost per GB, HDDs are the clear winner. A typical 60 GB consumer-grade SATA SSD costs about $200. The comparable HDD costs $50 or less. Most industry analysts do not see gigabyte per dollar parity between SSDs and HDDs on the horizon any time soon.

An example family of SSDs is WD’s SiliconDrive III series.  It delivers solid solutions for AdvancedTCA-based media streaming applications requiring high performance and reliability. Technologies integrated into the SiliconDrive III products solve industry problems and increase reliability substantially, namely:

* PowerArmor eliminates drive corruption from power disturbances
* SiSMART delivers real-time data on SSD useable life
* SolidStor ensures multi-year product life
* LifeEST forecasts SSD endurance in months or years

AdvancedTCA-based applications operate in demanding environments, making the selection of the appropriate storage platform critical. Endurance, ruggedness, and reliability are key factors in choosing the optimal storage solution that meets system performance. By matching their usage model and budget requirements with advanced storage technologies, TEMs can improve cost/performance tradeoffs significantly with SSDs.

Gary Drossel is Director of Product Planning at Western Digital (WD). You can reach him at gary.drossel@wdc.com.