http://www.tomsitpro.com/article ... -iomemory-sx300-ssd,2-1004-2.html
![]()
The ioMemory card does not feature any DRAM on the PCB because it utilizes the host RAM for SSD management purposes. The DRAM usage per card varies upon the type of format that users select, and the ioMemory cards default to the 4K sector format to minimize DRAM usage. However, most applications and key operating systems, such as ESXI, do not support 4k sectors. The majority of users will need to utilize the 512-byte format scheme that incurs much higher RAM requirements—nearly 8x the amount of DRAM for the 3.2TB model in comparison to the 4K sector format.
The amount of RAM listed in the chart seems daunting—it can take up to 57.8GB of RAM for a 3.2TB SSD, but SanDisk advises that these are worst-case figures. In comparison, offloaded architectures with onboard ASICs, like the competitors we will be testing the SX300 against today, manage just as much flash capacity with roughly 4GB of low-power onboard DRAM. It is important to note that the majority of I/O requests are 4K even if the application requires 512-byte support, so actual RAM usage will likely be much lower with 512-byte formatting. Users will need to conduct POCs (proof of concept) to ascertain the impact on each unique environment.
|