Data centers all around the world are pushing the available technology to its limits, in the struggle to increase main memory capacity and bandwidth, while reducing latency. After several years of being relegated to small niches, it seems like nonvolatile dual-inline memory modules (NVDIMMs) have suddenly surfaced into the limelight. According to the Objective Analysis NVDIMM market model, the market for NVDIMMs is poised to grow at an 105% average annual rate to nearly 12 million units by 2021. Read below a quick guide to understanding NVDIMMs and why this technology is a game changer for computer storage.
Disrupting the existing memory and storage hierarchy
While the processing speeds of the microprocessors are constantly increasing, the performance levels of hard disk drives have stayed about the same for many years. The introduction of NAND-based SAS and SATA interface SSDs brought an important improvement, but the raw performance of the NAND chip itself has stayed pretty constant over the last several years. Moreover, as DRAM scaling is slowing, DIMM capacities have not been increasing at the rate needed. All of this led the industry to chase multiple next-generation memory solutions that have the potential to break the standard memory and storage hierarchy. Emerging memory technology such as NVDIMM-N and NVDIMM-P is the logical next step since the integration of this tech helps with the improvement of applications that require higher throughput, while simultaneously offering fault-tolerant data integrity. Non-volatile DIMM cards may also be used to supply high-performance storage or extend system memory.
Performance, security, low power consumption
NVDIMM aims to improve the performance of various devices in terms of storage, online transactions, indexing, cache, logging, message queuing, batch processing and RAID (redundant array of independent disk). An NVDIMM allows software to perform a single write to a persistent memory address, resulting in a dramatic speed improvement.
Nowadays many applications are designed to deliver the highest possible performance and reliability, by taking full advantage of the features of both SSDs and DDR memory. However, a sudden power failure may damage critical data stored in the DDRAM memory, corrupting the files. For example, unexpected data loss could result in the failure of financial transactions, leaving the data unrecoverable or corrupted. As a solution to this problem, NNVDIMMs are designed to maintain their contents for long periods of time even when power is lost.
The power consumption problem is now history for these emerging memories, as all are nonvolatile so there’s no need to refresh them. Compared to DRAM their power consumption is reduced by 20%. All of them can overwrite old data without erasing, thus saving the high erase energy consumption required for flash, and the delays incurred by the slow erase cycle. Write energy requirements for these new technologies are extraordinarily low compared to those of flash, reducing or removing the need for an inefficient charge pump.
Variations of NVIDMMs
Best described as a battery-backed DRAM, the NVDIMM-N is the first storage solution emerged from this tech. When the CPU is using it, the DIMM operates just like a standard DRAM, but when a power failure occurs, data is immediately moved from the DRAM to backup NAND on the DIMM itself. This ensures the data in memory is never lost, serving as an emergency backup system.
NVDIMM-F is a storage solution that sits on a DRAM DIMM bus with multiple controllers and a bridge to convert the DRAM bus interface to multi-channel SATA protocols. This solution has the capability to block addressing, where a host system has the capability of using a moving address window to access the entire flash content.
The NVDIMM-P specifications are expected to be released by JEDEC Solid State Technology Association this year. According to JEDEC, the new standard will allow storage inside the computer main memory, using ReRAM technology, and a DDR5 interface. An NVDIMM-P has a persistent DRAM and can access external block-oriented (flash memory) drive for memory cache.
Intel’s breakthrough in non-volatile memory technology goes mainstream
Intel Optane technology is a unique combination of Intel 3D XPoint memory media with Intel-built advanced system memory controller, interface hardware and software IP. Earlier this year, the company announced the Intel® Optane™ SSD 800P, the latest addition to the growing Intel Optane technology family of products. According to Intel, the new product enables fast system boot, speedy application load times and smooth multitasking. It is ideal for use as a standalone SSD, in a dual drive setup or in a multiple SSD RAID configuration (PCH-based or CPU-based), offering performance and flexibility to users. The drive also supports lower-power states, allowing it to operate on devices like laptops and 2-in-1 devices, as well as desktop systems.
