SSDs incorporated into today’s data centers are generally based on flash technologies, and when marketing their products vendors tend to focus on highlights such as throughput, latency and IOPS. But experts note there’s more to flash-based SSD’s then that.
For example, tech writer Robert Sheldon recently explained that “the components that make up a flash drive include the NAND cells that store the data, as well as a storage controller, interface and cache buffer, all of which play a pivotal role in solid-state drive performance.”
According to Sheldon, the original flash drives were based on a single-level cell (SLC) structure that stored 1 bit per cell, but NAND cell technology has evolved – first through multi-level cell drive, which supported 2 bits per cell, and after that, the triple-level cell (TLC) drive, which stores 3 bits per cell – to now support greater capacities and also drive down prices.
“With TLC, flash drives can support higher capacities than ever. They exceed many of their hard disk drive counterparts” Sheldon explained, but he added that current “TLC drives cannot always deliver the same levels of performance as the original SLC drives. Newer 3D NAND technologies (however) promise to deliver both capacity and performance -- once manufacturing costs are brought in line with other NAND technologies.”
In Sheldon’s view, other factors -- the drive's component architecture and how it handles write amplification -- can be equally important in determining how well a drive will perform over its lifetime.
Moreover, “there are other considerations that go into implementing SSDs in a data center, such as the available server and network resources as well as the operating systems running on those servers. But the drive's components and write amplification methodologies should be top concerns.”
Only by taking into account all these factors, Sheldon said, can organizations ensure that the drives they purchase will deliver the performance necessary to support their applications.