Kingston SSDNow Solid-State Drives (SSDs), incorporating LSI® SandForce® controllers, feature Data Reduction technology that enhances their usable life and performance.
NAND Flash technology is a non-volatile memory technology that is subject to wear when host writes are performed. SSDs are rated in Total Bytes Written (TBW), which
lets users calculate the estimated life of SSDs based upon their daily writes. Except in extreme cases, the majority of SSDs installed in Client systems such as desktops, notebooks and ultrabooks will outlast the systems.
Most data on Client systems is compressible, according to an LSI study, shown in Figure 1 below:
Figure 1: File compressibility based upon WinZip measurements
(Lower numbers mean the files are more compressible; 100% means they are incompressible)
Data Reduction technology, for the purposes of this brief, is similar to data compression. Kingston’s SSDs with LSI SandForce controllers compress data being written to the NAND Flash storage. This compression reduces the footprint of the data being written to the SSD, thereby generating Dynamic Over Provisioning as a benefit.
Kingston SSDs generally have about 7 percent extra NAND Flash storage reserved for the SSD controller’s use (that is why capacities show 120GB for a 128GB SSD, and similarly for 240GB/256GB and 480GB/512GB SSDs). This OP space is used to support the SSD controller’s operations.
However, through DuraWrite Data Reduction technology, the smaller footprint of data written to the NAND Flash storage creates Dynamic OP by freeing up additional OP space.
The following example (courtesy of LSI) will illustrate this benefit:
Let’s assume we have a standard 256GB SSD filled to 80 percent capacity with a typical operating system, applications and user data. The SSD has 20 percent free space, used by the SSD controller as its Dynamic OP. Next, let’s take the same SSD with DuraWrite Data Reduction technology and compare them in Figure 2:
Figure 2: SSD without Data Reduction vs. SSD with DuraWrite (Graphs courtesy of LSI)
Both SSDs have the standard OP area for a 256GB SSD (shown in the “Over Provisioning” box in dark green), followed by the free space area that functions as Dynamic OP for both types of SSDs.
However, in the SSD with DuraWrite Data Reduction technology on the right, we can see that the footprint of the Operating System, applications, and some of the user data (the compressible portion) is smaller – resulting in less NAND Flash capacity being utilized on the SSD to store data. While both SSDs have 20 percent free space, the SSD on the right with DuraWrite technology has an Incremental Dynamic OP area that it can utilize to increase the SSD’s performance and extend its endurance even more than the standard SSD shown on the left.