Intel® Optane™ DC Persistent Memory Technical Video
This video is technical in nature and it will explain the need for a new tier in the storage/memory hierarchy and salient details of Intel® Optane™ DC persistent memory functionality, configuration with a focus on Memory mode and App Direct mode.
The world's data is growing exponentially, with a five-fold increase on existing data forecast by 2025. 30% of that data, more data than currently exists, is expected to be processed in real time. The challenge is no longer just about acquiring or building infrastructure to contain data, but includes focus on extracting insights fast enough to achieve a sustainable competitive advantage.
Removing infrastructure bottlenecks and aligning technologies to specific workloads is therefore essential to business data strategy. From a data-tiering perspective, the increasing demand for real-time analytics implies an increasing amount of hot data requiring high bandwidth, low latency accessibility close to the CPU.
While DRAM delivers low latency and cache line granularity required to keep data close to the CPU, it is costly to implement and volatile. In addition, the rate of growth in DRAM density is slowing. Analyzing the rate of density growth since 1985 shows a decrease from a fourfold density increase every three years to a twofold density increase every three years to a twofold increase every four years. This slowing rate of growth in DRAM density creates an increasing gap between data and memory capacity.
NAND-based SSDs have the capacity and cost structure to scale, but by design only offer block granularity accessible over the I/O bus, as they are intended for storage, not memory function. There is, however, a technology that delivers memory with persistence at a lower capacity cost compared to DRAM, and lower latencies with higher endurance than NAND.
Intel Optane memory media is fundamentally different to traditional DRAM and NAND technologies. Memory cells are manufactured from a unique combination of materials that, unlike DRAM, provide data persistence, and are stacked in a three-dimensional matrix for higher densities. The data access array supports granular addressing, promoting faster access and improved endurance compared to NAND.
One of the many benefits offered by the innovative architecture is that it can be deployed in a variety of form factors that can connect to either the memory channel or the storage bus to provide a wide range of memory and storage solutions. Deployed in an Intel Optane SSD, it provides data access over the storage bus with significantly lower latency, higher bandwidth, and endurance than a NAND-based SSD. Implemented as part of Intel Optane DC persistent memory, it provides high speed, low latency, and high-capacity data access with persistence.
Available in 128, 256, and 512 gigabyte capacities, and installed in DDR4 slots, Intel Optane DC persistent memory modules have built-in enterprise-class reliability, availability, and serviceability features and first-ever hardware encrypted memory. The persistent memory controller on each module provides a platform interface and supports advanced features.
The integrated memory controller in second generation Intel Xeon scalable processors has been enhanced to support communication with DDR4 memory and Intel Optane DC persistent memory modules in the same system. Modules should be installed according to DIMM population guidelines, and configured for targeted memory function.
Address space on Intel Optane DC persistent memory modules can be provisioned for use in specific modes, depending on intended usage. Memory Mode brings large memory capacity, and does not require application changes, which makes Intel Optane DC persistent memory easy to adopt. The CPU memory controller uses DRAM as cache and Intel Optane DC persistent memory as addressable main memory.
Virtualization can benefit from larger memory capacity to support more VMs and more memory per VM at a lower cost compared to DRAM. Workloads that are I/O bound can also benefit from the larger memory capacity, which supports larger databases, and at a lower cost, compared to DRAM. Memory Mode does not provide data persistence, and App Direct Mode should be configured if data persistence in memory is required.
In App Direct Mode, the applications and operating system are explicitly aware there are two types of direct load-store memory in the platform. They can direct operations that require the lowest latency, and don't need permanent data storage to be executed on DRAM. And data that needs to be made persistent can be routed to the Intel Optane DC persistent memory. It is persistent like storage, byte addressable like memory, and cache coherent, which extends the usage of persistent memory outside the local node and consistent low latency supporting larger data sets.
The power of persistent memory adds business resilience to systems with faster restart times, because data is retained, even during power cycles. Memory-bound workloads benefit from Intel Optane DC persistent memory, with its large capacity and higher endurance and greater bandwidth, compared to NAND SSDs.
In App Direct Mode, capacity can be made accessible via standard file APIs, supported by compatible hypervisors, as well as compatible Windows and Linux operating systems. This allows existing storage-based applications to access the app direct region of Intel Optane DC persistent memory without any modifications to existing applications or file systems that expect block storage devices, providing high performance block storage without the latency and processor overhead incurred when moving data to and from the I/O bus.
Intel Optane DC persistent memory requires configuration before the operating system can access the media. Management interfaces provide capabilities including discovery, provisioning, maintenance, and monitoring of Intel Optane DC persistent memory modules at the system level. Intel Optane DC persistent memory can be managed in the pre-boot UEFI/EFI shell and compatible operating system environments, using the persistent memory control command line utility, or programmatically, using the native API library for Intel Optane DC persistent memory.
Regions are created when capacity is designated for either Memory Mode or App Direct Mode from available Intel Optane DC persistent memory. For persistent memory, the regions can be configured on non-interleaved or interleaved sets, and capacity is limited to the boundaries of the interleaved set. Regions can then be divided into one or more namespaces using operating system vendor tools for the capacity to be surfaced to the operating system and used by applications.
Just as an SSD can be divided into namespaces, persistent memory names spaces represent the unit of storage that appears as a device that can be used for I/O. From a maintenance perspective, persistent memory module firmware should be updated in line with established change management processes to ensure necessary fixes and updates are applied.
Persistent memory modules have an overall health state and indicates a roll up of underlying Intel Optane DC persistent memory and controller health status. Alarm thresholds can be customized to support in-band and out-of-band monitoring. Documented procedures for adding, removing, replacing, or reprovisioning Intel Optane DC persistent memory modules should be followed to avoid unnecessary data loss.
Intel partners with multiple industry groups and industry leaders to provide an ecosystem and updated specifications for using persistent memory. This includes the persistent memory development kit with Intel-validated performance tuned libraries that are open-source and product-neutral, meant to make persistent memory programming and adoption easier. There are many resources intended to promote your success with design, testing, implementation, and support of Intel Optane DC persistent memory in your organization. Please follow the links below for further information.