One of the key attributes of flash storage is its ability to remove storage I/O latency. The memory based storage technology can respond instantly to requests for data. However, flash’s zero latent nature exposes latency in other parts of the I/O path. The result is that the CPU can’t get responses to its I/O requests as fast it should and flash is not able to live up to its full performance potential.
The first step in removing some of this latency was by moving from a drive form factor SSD that had to communicate through the storage protocol interconnect and put flash directly on the PCIe bus via PCIe SSDs. But PCIe SSDs still had to deal with contention that caused latency. For example there are other I/O cards on that PCIe bus that are using the same I/O path that the PCIe SSD was. As a result latency was reduced compared to drive form factor SSDs, but there was potential to reduce it even more.
Companies like SanDisk, formally SMART Storage Systems, have announced a new DIMM slot based technology that leverages the memory I/O path for storage instead of the PCIe Bus or a storage interconnect to cross the final frontier in latency removal. In this video, George Crump, Lead Analyst with Storage Switzerland and John Scaramuzzo, SanDisk’s Senior Vice President of Storage Solutions, discuss the I/O bottleneck challenges that flash based storage has faced and how their new ULLtraDIMM technology overcomes them.