Discover the separate and combined capabilities of Hard Disk Drives and Solid-State Drives
In this section we will discuss both the separate and combined capabilities of HDD and SSD. While HDD has dominated the online storage industry for the past few decades, the maturity, performance, and reliability of solid state storage technology or flash technology is on the rise. Rather than replacing all of your HDD, consider a hybrid configuration of HDD and SSD that combines to create great price/performance synergy. Offering a considerable competitive advantage, it's not a question of if solid-state drives will be part of your computer center, but rather when.
HDD = Hard Disk Drive
As the inventor of the first commercial HDD in 1956, IBM proved to be a leader in storage innovation. Today, HDD is a proven technology with excellent reliability and performance, given the physical limitations of its spinning platters and moving arms. In fact, IBM has helped invent many of the work-around technologies such as adapters with read and write cache, which help address some of these physical bottlenecks.
As for the many systems that are not I/O bound, HDD performance is often very acceptable due to the work of IBM and the rest of the industry. Although the amount of capacity per drive, storage density, and cost per GB of HDD has improved continuously over time, the time it takes to access information has remained fairly constant for years. As processors and memory continue to increase in speed, the gap between memory and HDD speed incessantly widens. With an irresistible cost per GB, HDD will continue to be a key storage technology for years to come.
SSD = Solid-State Drive
Also known as Flash technology, solid-state drive technology eliminates the rotational delay of a spinning platter and of waiting for an arm to move to the correct position. Thus, data is available nearly immediately! Dramatically reducing crippling I/O bottlenecks, an SSD provides up to 33X to 250X* more I/O Operations Per Second (IOPS) than a HDD and works at speeds much closer to those of memory, helping to bridge the HDD performance gap.
SSDs are also more efficient than HDD. While SSD can operate close to 100% capacity, HDD is often limited to 20-50% storage capacity in an effort to improve responsiveness. SSD provides better performance while also reducing foot print and energy consumption; only a few SSDs can replace many HDD. Furthermore, advances in technology have allowed IBM Power Systems to provide enterprise class SSDs, which have the sustained high performance capabilities and rugged, long-life endurance that earlier generation Flash drives and many of today's consumer class cannot provide.
Although HDD cost/GB is lower than that of SSD, solid-state drives boast a cost/performance that can’t be beat. SSD can enable analytical applications which were not cost/time effective previously. SSD can slash I/O-bound batch windows by up to 50%, while also improving response time and throughput. SSD can speed up critical response time applications to allow people and systems to more quickly react and provide higher service level to the business. Specializing in high I/O performance, SSD has the upper hand in cost/IOPS.
SSD can be found in these two types of solutions:
|Foot print||Replaces several HDDs with just a few SSDs||Significantly more HDDs required than SSDs to achieve same level of performance|
|Energy||Saves energy by replacing many HDDs||Having many more HDD burns energy, especially old 3.5" HDD|
|Price performance||Excels in cost/IOPs||Excels in cost/GB|
|Capacity used||Can operate close to 100%||Often operates 50% or less|
|Data configuration||Leverages hot and cold data / data placement on both SSD and HDD||Holds both hot and cold data|
|System protection schemes||Hot plugging, mirroring, and RAID||Hot plugging, mirroring, and RAID|
Hybridization: Solid-State Drives and Hard Disk Drives join forces
We have now seen the separate and powerful capability sets that both HDD and SSD offer, but remember, two heads are better than one! The combination of HDD and SSD allow each type of storage to perform at its best; the HDD can be focused on “cold” data that is not often used, while the high IOPS/sec capability of SSD is focused on the “hot,” frequently accessed data. The high performance capabilities of SSD and the undeniable HDD storage cost effectiveness compliment one another in a hybrid configuration that achieves the most effective level of price performance.
Now that we have discussed the fundamental differences and integration opportunities of HDD and SSD, we will examine 2 types of solid-state drive: Internal Solutions which is also called Direct Access Storage (DAS) and Storage Area Networks (SAN).
* The wide range of improvement (33X – 250X) is based on workload specific characteristics such as the mix of writes vs reads, presence of SAS controllers with write cache, randomness of the data, small vs large blocks of data, which generation of SSD technology used, and other factors.