Optane Technology: Memory or Storage?

This is a technology brief by Intel Corp.

Intel Optane Technology: Memory or Storage? Both

Not NAND-based and not DRAM:
this industry disrupting technology takes the best of both
to establish new tiers in the memory/storage hierarchy.

The stakes are high in today’s data centers. Organizations have access to massive quantities of data promising valuable insights and new opportunities for business. But data center architects need to rethink and redesign their system architectures to ingest, store, and process all that information. Similarly, application owners need to assess how they can process data more effectively. Those who don’t re-architect might find themselves scrambling just to keep from being drowned in a data deluge.

The challenge for storage architects is that memory and storage solutions have historically been limited by capacity, performance, or cost. For example, traditional DRAM is great for in-memory processing of data at high speeds, but it’s expensive and limited in capacity and scalability. NAND-based storage, such as traditional SSDs, offers greater capacity and a lower cost relative to DRAM, but it can’t offer the same levels of performance. HDDs can provide massive storage at low prices, but spinning disks bring well-understood TCO issues around reliability, physical space requirements, cooling, and much more. These memory and storage limitations result in data center architecture gaps when trying to balance capacity, performance, and cost considerations.

Figure 1. Optane technology fills memory and performance gaps in the data center

New Approach to Memory and Storage
Intel is pioneering a new approach for data center architectures that closes the gap between traditional memory and storage. The keystone to this approach is Optane technology. It is not based on NAND; it’s a new technology built on an architecture that allows memory cells to be individually addressed in a dense, transistor-less, stackable design.

It comprises Optane memory media combined with system memory and storage controllers, along with interface hardware and software enhancements, as shown below.

Figure 2. Optane technology combines Optane memory media
with Intel memory controllers and specialized hardware and software

Memory and Storage Flexibility
Optane technology is fundamentally different from both traditional DRAM and NAND-based drives, but it offers characteristics of both.

The key to the technology is Optane memory and storage media: a new memory architecture that stacks memory grids in a 3D matrix to improve density, increase performance, and provide persistence (Figure 3). This media architecture allows Optane technology to act like DRAM (byte addressability, high endurance, write in place) or traditional storage (block addressability, persistence), depending on the use case or product configuration. That capability offers significant performance advantages compared to traditional NAND media-based drives. For example, because Optane technology allows memory cells to be individually accessed and updated, there’s no need for garbage collection. As a result, Optane memory and storage media offers speeds close to DRAM, with the persistence of traditional SSDs.

One of the benefits offered by the 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 range of memory and storage solutions for storage designers.

Figure 3. Optane memory and storage media offers properties of both memory and storage
by using a 3D structure that provides high density, low latency, and persistence

Optane Technology as Persistent Memory
Optane DC persistent memory in App Direct Mode delivers Optane technology as persistent memory modules, which plug into standard DIMM slots on the memory channel. Unlike traditional DRAM, Optane DC persistent memory offers 2 important features to change memory and storage: persistence, which means data is retained even in the event of a power loss or restart, and high density-up to 512GB per DIMM, which is double the maximum density of current DRAM DIMMs.

Applications that have been optimized for Optane DC persistent memory avoid the significant software overhead of IO operations and instead benefit from much faster low-latency memory-access operations. This advantage enables organizations to transform their systems and services to deliver new advancements across a range of data center use cases, including improved analytics with in-memory databases, high-performance in-memory computing, AI, high-capacity VMs and containers, and CDNs.

Optane DC persistent memory also reduces in-memory database restart times because the database does not have to be reloaded into volatile memory after a shutdown. And it, organizations can more affordably scale system memory capacity to unprecedented levels because the cost per gigabyte of memory is lower with Optane DC persistent memory modules, compared to traditional DRAM DIMMs.

Optane Technology as Volatile Memory
Optane DC persistent memory in Memory Mode enables applications to make use of Intel Optane DC persistent memory as expanded volatile system memory. It offers the advantage of additional system memory capacity (module sizes up to 512GB), without needing to rewrite software.

Optane DC SSDs as memory-mapped I/O let businesses extend their DRAM for select Linux applications. One way to do this is to configure the Optane SSD DC P4800X to use Intel Memory Drive Technology, which allows users to grow a server’s volatile memory beyond DRAM capacity limits, or to replace high-capacity DIMMs with a higher-capacity, lower-cost/GB alternative that can provide similar performance to DRAM.

In addition, Memory Drive Technology requires no changes to application software. This capability is particularly beneficial to businesses and researchers in genomics, the pharmaceutical industry, radiology, and other fields that face a growing hunger for memory and storage, but that are constrained by the high cost and limited density of DRAM or the need for a large memory footprint.

Optane Technology as Storage
Optane DC persistent memory in Storage Over App Direct Mode makes persistent memory address space accessible through standard file APIs supported by current gen hypervisors and Windows and Linux OSs. This allows existing storage-based applications to access the App Direct region of Optane DC persistent memory modules without any modifications to the existing applications or the file systems that expect block storage devices. Storage over App Direct Mode provides high- performance block storage, without the latency of moving data to and from the I/O bus.

Table 1. Comparison of memory and storage:
Optane DC Persistent Memory DIMMs and Optane DC SSDs

Optane DC SSDs enable an entirely new storage tier between Optane DC persistent memory and NAND SSDs that brings data closer to the processor for fast caching or fast storage of hot and warm data. In contrast to traditional NAND-based SSDs, Optane DC SSDs aren’t limited to a “sweet spot” for peak performance. Optane technology provides high random R/W performance, along with consistent, low latency that is for demanding database applications that require frequent, high-speed caching, logging, or journaling. Businesses can take advantage of this benefit by deploying Optane DC SSDs to accelerate caching, as an alternative to using large quantities of costly, limited-capacity DRAM. With this strategy, organizations can deploy Optane DC SSDs for caching, and high-capacity Intel QLC NAND-based SSDs as affordable capacity storage.

Optane DC SSDs also offer high endurance and QoS, which makes them a good fit for write-intensive uses, such OLTP, HPC, and data caching and logging.

In particular, Optane DC SSDs provide consistent, high performance under load, reaching peak performance at lower queue depths, where nearly all real-world applications operate. In comparison, traditional NAND storage drives often reach optimum performance levels only at higher queue depths-beyond the usable range of most applications. Peak performance at higher queue depths does not accurately reflect real-world drive performance. As a result, Optane DC SSDs offer enhanced performance for applications, compared to NAND-based SSDs.

Quickly Access More Data with Optane Technology
The versatility of Optane technology allows organizations to deploy a solution that best meets their specific business needs and workloads. For example, when performance and persistence are key, Optane DC persistent memory offers an option, while still supporting capacities much greater than standard DRAM. For organizations that need even greater memory capacities, Optane DC SSDs with Memory Drive Technology offer high capacities and flexibility to be used as memory or storage as needs change over time.

Many businesses can achieve significant gains in performance, capacity, and overall cost savings by simply deploying Optane DC persistent memory and Optane DC SSDs in their data centers. For example, most organizations run transactional databases as part of their operations. These businesses can create cost-effective solutions for transactional workloads by using low-latency Optane SSD DC P4800X drives in the cache tier instead of standard NAND SSDs to handle write operations, while using Intel QLC 3D NAND SSDs in the capacity tier to handle read operations. This combination can lower operating costs while providing performance.

As another example, businesses can use Optane DC persistent memory to extend or displace DRAM and move more data into memory for in-memory database platforms, like the SAP HANA platform. Higher memory densities mean that enterprises can consolidate larger transactional and analytics systems into the same physical space, which can help reduce costs in the data center.

These are just a few of the many ways Optane technology can transform modern data centers. It is for all types of devices, applications, and services requiring fast access to large sets of data. The architecture removes performance bottlenecks to optimize CPU utilization for platforms powered by Intel Xeon Scalable processors. That optimization can allow businesses to achieve:
• More transactions for sales
• Faster insights from larger datasets for analytics
• Greater productivity for creative work
• Deeper understanding of data for scientific research